Crystal Structure and Thermochemical Properties of 2-Pyrazine Carboxylate Lithium Monohyd

材料科学基础重要概念（中英文）晶体学基础晶体学（crystallography）布喇菲点阵（Bravais lattice）晶体生成学（crystallogeny）体心化（body centering）晶体结构学（crytallogy）底心化（base centering）晶体化学（crystallochemistry）特殊心化（special centering）晶体结构（crystal structure）晶面（crystal plane）点阵平移矢量（lattice translation vector）晶（平）面指数（crystal – plane indice）初级单胞（primitive cell）晶带（zone）点阵常数（lattice parameter）倒易空间（reciprocal space）对称变换（symmetry translation）参考球（reference sphere）主动操作（active operation）经线（longitude）国际符号（international notation）赤道平面（equator plane）点对称操作（point symmetry operation）极网（pole net）旋转操作（rotation operation）结构基元（motif）二次旋转轴（two - fold axe, diad）晶体几何学（geometrical crystallography）四次旋转轴（four – fold axe, tetrad）晶体物理学（crystallographysics）镜像（mirror image）等同点（equivalent point）对形关系（enantiomorphic relation）点阵（lattice）反演（inversion）初基矢量（primitive translation vector）晶系（crystal system）复式初基单胞（multiple – primitive cell）单斜晶系（monoclinic system）对称元素（symmetry element）四方晶系（正方晶系）（tetragonal system）对称群（symmetry group）六方晶系（hexagonal system）被动操作（passive operation）熊夫利斯符号（Schoenflies notation）点阵有心化（centering of lattice）恒等操作（单位操作）（identity）面心化（face centering）旋转轴（rotation axe）单面心化（one – face centering）三次旋转轴（three – fold axe, triad）晶向（crystal direction）六次旋转轴（six – fold axe, hexad）晶向（方向）指数（crystal – direction indice）镜面（mirror plane）晶面族（form of crystal - plane）同宇（congruent）倒易点阵（reciprocal lattice）旋转反演（rotation - inversion）极射赤面投影（stereographic projection）三斜晶系（triclinic system）参考网络（reference grid）正交晶系（斜方晶系）（orthogonal system）纬线（latitude）立方晶系（cubic system）吴氏网（Wulff net）菱方晶系（rhombohedral system）标准投影网（standard projection）晶体结构晶体结构（crystal structure）鲍林规则（Pauling’s rule）结构符号（structure symbol）氧化物结构（oxide structure）致密度（空间填充效率）（efficiency of space 岩盐结构（rock structure）filling）纤维锌矿结构（wurtzite structure）配位数（coordination number）闪锌矿结构（zinc blende structure）配位多面体（coordination polyhedra）尖晶石结构（spinel structure）拓扑密堆相（topologically close – packed α-Al2O3型结构（corundum structure）phase）金红石结构（rutile structure）金属晶体（metal crystal）萤石结构（fluorite structure）离子晶体（ionic crystal）钙钛矿结构（perovskite structure）共价晶体（covalent crystal）钛铁矿结构（ilmenite structure）分子晶体（molecular crystal）氯化铯结构（cesium chloride structure）原子半径和离子半径（atomic radius and ionic 硅酸盐（silicate）radius）链状硅酸盐（chain silicate）原子结构体积（volume of structure per atom）层状硅酸盐（phyllo silicate）体密度（volumetric density,ρV）岛状硅酸盐（island silicate）面密度（planar density, ρP）骨架结构（framework structure）线密度（linear density, ρL）镁橄榄石结构（forsterite structure）金刚石结构（diamond structure）辉石（picrite）纳米碳管（carbon nano tube）粘土矿（clay mineral）置换固溶体（substitutional solid solution）高岭石（kaolinite）填隙固溶体（interstitial solid solution）云母（mica）尺寸因素（size factor）石英（quartz）价电子浓度（valance electron concentration）鳞石英（tridymite）电子化合物（electron compound）方石英（cristobalite）间隙化合物（interstitial compound）钙长石（anorthite）尺寸因素化合物（size–factor compound）分子筛（molecule sift）Laves相(Laves phase) 同素异构性（allotropy）σ相（σphase）多形性（polymorphism）有序固溶体（超结构）[ordered solid solution 准晶（quasicrystal）(super lattice) ] 彭罗斯拼砌（Penrose tiling）长程有序参数（long-range order parameter）短程有序参数（shot-range order parameter）晶体缺陷不完整性（imperfection）向错（disclination）点缺陷（point imperfection）沃特拉过程（V olterra’s process）空位（vacancy）刃型位错（edge dislocation）自间隙原子（self-interstitial）螺型位错（screw dislocation）构型熵（configuration entropy）混合型位错（mixed dislocation）肖脱基缺陷（Schottky defect）柏氏回路（Burgers circuit）弗兰克缺陷（Frenkel defect）柏氏矢量（Burgers vector）内禀点缺陷（intrinsic point defect）位错环（dislocation loop）非禀点缺陷（extrinsic point defect）位错密度（dislocation density）线缺陷（line imperfection）位错的弹性能（elastic energy of dislocation）位错（dislocation）位错线张力（tension of dislocation）位错宽度（width of dislocation）层错矢量（fault vector）保守运动（conservative motion）外延层错（extrinsic fault）非保守运动（nonconservative motion）层错能（stacking fault energy）滑移（slip）肖克莱部分为错（Shockley partial dislocation）滑动（glissile）铃木气团（Suzuki atmosphere）攀移（climb）弗兰克位错（Frank partial dislocation）自力（self-force）扩展位错（extended dislocation）渗透力（osmotic force）压杆位错（stair-rod partial dislocation）映像力（image force）Lomer-Cottrell 位错（Lomer-Cottrell弯结（kink）dislocation）割阶（jog）L-C阻塞（L-C Lock）柯垂尔气体（Cottrell atmosphere）赫斯阻塞（Hirth lock）史诺克气体（Snoek atmosphere）分位错（fractional dislocation）弗兰克-瑞德位错源（Frank-Read source）超点阵（superlattice）B-H位错源（Bardeen-Herring source）反相畴（Antiphase domain）位错塞积群（dislocation pile-up group）反相畴界（Antiphase boundary, APB）全位错（perfect dislocation）超位错（super-dislocation）堆垛层错（stacking fault）弗兰克-纳巴罗回路（Frank-Nabarro circuit）部分为错或不全位错（partial dislocation）向错强度（disclination strength）内禀层错（intrinsic fault）条纹织构（schlieren texture）表面能(surface energy) 适配(matching)晶界(grain boundary) 共格晶界(coherent boundary)小角度晶界（low angle grain boundary）非共格晶界(incoherent boundary)大角度晶界（high angle grain boundary 晶界迁移率(grain boundary mobility)倾转晶界（tilt boundary）取向关系(orientation relationship)扭转晶界（twist boundary）气泡(gas babble)相界(phase boundary) 空洞(void)扩散不可逆过程（irreversible process）传质过程（mass transport）扩散（diffusion）扩散距离（diffusion distance）唯象系数（phenomenological coefficient）间隙机制（interstitial mechanism）挤列结构（crowdion configuration）哑铃结构（dumbbell split configuration）空位机制（vacancy mechanism）换位机制（exchange mechanism）扩散流量（flux）参考系（reference frame）实验参考系（laboratory reference frame）点阵参考系（lattice reference frame）菲克第一定律（Fick’s first law）菲克第二定律（Fick’s second law）扩散系数（diffusion coefficient）禀性扩散系数（intrinsic diffusion coefficient）互扩散系数（mutual diffusion coefficient）自扩散系数（self-diffusion coefficient）稳态扩散（steady state diffusion）Kirkendall 效应（Kirkendall effect）Matano 平面（Matano interface）热力学因子（thermodynamic factor）同位素（isotope）示踪物（tracer）扩散偶（diffusion couple）误差函数（error function）哑变量（dummy）数值方法（numerical method）有限差分（finite-difference）收敛性（convergence）截断误差（truncation error）舍入误差（round-off error）相关系数（correlation factor）高扩散率通道（high-diffusivity path）体扩散（volume diffusion）晶界扩散（grain boundary diffusion）位错扩散（dislocation diffusion）表面扩散（surface diffusion）迁移率（mobility）渗透率（permeability）凝固分配系数（partition coefficient）枝晶偏析（dendrite segregation）区域提纯（zone-refining）亚共晶合金（hypoeutectic alloy）胞晶的形成（cell formation）过共晶合金（hypereutectic alloy）胞状树枝晶（cellular dendrite）片状（lamellar）柱状树枝晶（columnar dendrite）棒状（rod-like）共晶凝固（eutectic solidification）共晶领域（eutectic colony）包晶凝固（peritectic solidification）伪共晶（pseudo-eutectic）偏析（segregation）离异共晶（divorced eutectic）熔焊（fusion welding）激冷区（chill zone）快速凝固（rapid solidification process）柱状晶区（columnar zone）连续铸造（continuous casting）等轴晶区（equiaxed zone）树枝状显微偏析（dendritic microsegregation）收缩晶区（shrinkage cavity）非平衡杠杆定律（non-equilibrium lever rule）疏松（porosity）组分过冷（constitutional supercooling）非金属夹杂物（non-metallic inclusion）胞状组织（cellular structure）熔池（weld pool）二次枝晶（secondary dendrite）混合区（composite region）一次支晶（primary dendrite）热影响区（heat-affected zone）。

THE CRYSTAL STRUCTURE OF THE b0PHASE INAl±Mg±Si ALLOYSS.J.ANDERSEN1,2,H.W.ZANDBERGEN2,J.JANSEN2,3,C.TRáHOLT2,U.TUNDAL4and O.REISO41SINTEF Materials Technology,Applied Physics,7034Trondheim,Norway,2National Centre for HREM,Laboratory of Materials Science,Delft University of Technology,Rotterdamseweg137,2628 AL Delft,The Netherlands,3Laboratory for Crystallography,University of Amsterdam,Nieuwe Achtergracht166,1018WV Amsterdam,The Netherlands and4HYDRO Aluminium,Metallurgical Rand D Centre,Sunndalsùra,Norway(Received17November1997)AbstractÐThe crystal structure of b0,one of the strengthening phases in the commercially important Al±Mg±Si alloys,is determined by use of high resolution electron microscopy(HREM)and electron di raction(ED).A trial structure was established from exit wave phase reconstructed HREM images.A least-square re®nement of the model coordinates was done using data from digitally recorded ED patterns.A recently developed computer program(MSLS)was applied,taking into account dynamic scattering.The atomic unit cell contains two units of Mg5Si6.It is C-centred monoclinic,space group C2/m, a=1.51620.002nm,b=0.405nm,c=0.67420.002nm,b=105.320.58.The atomic packing may be regarded as a hard ball packing using clusters,the clusters being(1)centred tetragons of Mg atoms and(2) so-called twin icosacaps where Mg atoms are centred above and below pentagonal rings of four Si atoms an one Mg atom.A growth related stacking fault in the structure is explained by a de®ciency of Mg atoms.A model for the b0/Al interface is given.#1998Acta Metallurgica Inc.1.INTRODUCTION1.1.GeneralThe discovery of the precipitation hardening mech-anism in the beginning of this century in an Al±Cu alloy has had great implications for all technologies requiring light alloys with some strength,and es-pecially for the aerospace and construction technol-ogies.The increase in hardness that the commercial Al alloys achieve upon hardening is usually a factor of2or more.In the Al±Mg±Si(6xxx)alloys such a tremendous increase in strength is caused by pre-cipitates formed from solution,of merely1wt%of Mg and Si that is added to the aluminium.The maximum hardness is achieved when the alloy con-tains a combination of very®ne fully coherent so-called Guinier Preston(GP-I)zones with diameters about2.5nm,and the semicoherent,larger needles, b0(GP-II zones)with a typical size4Â4Â50nm3. The density of these phases is very high.For the b0 needles,a number density in the matrix of about 104/m m3is normal.This is equal to a volume of nearly1%in the material.The6xxx series alloys are not among the strongest aluminium alloys,but they represent a high share of the aluminium pro-ducts in the world(H20%).In1989,about90%of the tonnage extruded in western Europe,was Al±Mg±Si alloys[1].1.2.The precipitation/transformation sequenceThe phases occurring in the Al±Mg±Si alloys have been studied for more than50years due to the commercial importance of these materials.In1948 Geisler and Hill[2]and Gunier and Lambot[3] reported that X-ray Laue pattern zones indicated the formation of small(H2Â2Â10nm3)needles or Guinier Preston(GP)zones,when the temperature was raised to2008C.Further heating caused the zones to thicken into rods,called b',and®nally a large plate-shaped equilibrium phase,b,was seen to form.The latter was known to be of the f.c.c.CaF2 type with a composition Mg2Si.The alloys that were studied were close to the Al±Mg2Si section of the Al±Mg±Si phase diagram;therefore it was assumed that the composition of all the Mg±Si con-taining phases was ter experiments have shown that the precipitation and transformation is quite complicated and that except for the equili-brium phase,b,the phases involved do not have the stoichiometric ratio Mg2Si.In Table1the transformation sequence at low ageing temperatures for alloys near the quasi-binary section Al±Mg2Si of the phase diagram is summar-ised.The range of existence and sizes of the b'rods and b plates depend not only on the heat-treatment, but on several other factors as well,such as cooling rate from homogenisation or extrusion and the number of Al±Fe(+Mn)±Si containing phases (dispersoids)in the material.This will not be dis-cussed in this paper.In the following a discussion of the precipitation/ transformation sequence shown in Table1is given.Acta mater.Vol.46,No.9,pp.3283±3298,1998#1998Acta Metallurgica Inc.Published by Elsevier Science Ltd.All rights reservedPrinted in Great Britain1359-6454/98$19.00+0.00 PII:S1359-6454(97)00493-X32831.2.1.Atomic clusters.After rapid cooling from homogenisation or extrusion the material is super-saturated with Mg and Si.Due to the higher solubi-lity of Mg in Al,when stored at room temperature or heated,Si ®rst goes out of solution and forms small clusters,but there are also some indications of clustering of Mg [5].The nucleation of Si-clusters will occur at quenched-in vacancies at temperatures as low as À508,below which the vacancy movement becomes very low [6].Storing or heating above À508will cause Mg to di use to the clusters,and Mg±Si phases will pre-cipitate.The di usion of Mg to the Si clusters has been veri®ed through APFIM [5,7]where the ratio of Mg/Si in the average cluster was found to increase with time when heated at 708.Since the number of Si clusters formed will be important for the precipitation of the strengthening GP zones,the storing time at a low temperature before arti®cial ageing is important concerning the material proper-ties.1.2.2.GP zones and the b 0phase .The ®rst phase to precipitate on the small clusters is the GP zones.Based on a TEM study of Al±Mg 2Si [8]Thomas proposed a model for these particles;Mg and Si replace Al in such a ratio that the occupied volume is about the same.He proposed a simple substi-tution along 110-directions with strings of atoms in the sequence Mg±Si±Mg±Mg±Si±Mg.Here two di-ameters of Mg (2Â0.32nm)and one of Si (0.235nm)amounts to 0.874nm,as compared with three diameters of Al (0.859nm).In more recent research the evolution of GP zones in several Al±Mg 2Si alloys was studied by calorimetry [6],in 6061by calorimetry and TEM [5],and by atom-probe ®eld-ion microscopy (APFIM)and TEM/HREM [5,7].These works support the view that there are at least two phases in the size range of the GP-zones,called GP-I and GP-II.For the GP-I type the size is in the range 1±3nm.The crystal structure is unknown.The zones are fully coherent and probably have a spherical shape.Dutta and Allen [9]observed by TEM small spot-like features of ``unresolved''shape of about 2.5nm that should be the GP-I zones.Particles investigated by APFIM [5]with comparable dimensions to these zones seem to have Mg/Si ratios usually less than 1.This composition is therefore di erent from that of the model proposed by Thomas [8].The GP-II zone is the same phase as the currently investigated b 0phase.This phase has the shape of ®ne needles,typically about 4Â4Â50nm 3when the material is in the aged-hardened condition [7,10].In this condition the number density of the nee-dles is high;typically 104/m m 3[10].The b 0phase is fully coherent only along the b -axis.Edwards et al.[7]managed to determine the unit cell of the b 0phase by electron di raction.It was found to be a monoclinic C-centred structure with a =0.153420.012nm,b =0.405nm,c =0.68320.015nm,b =10621.58.The b -axis is along the needle-axis.It is the full coherency of GP-I zones,the semi-coherency of the GP-II zones together with their high number densities that introduce in the alu-minium matrix strain and resistance against move-ment of dislocations,that gives the material its mechanical strength.1.2.3.The b 'phase .The next phase in the trans-formation sequence after the GP-I zones and the b 0phase is the b 'phase.This has a lower Mg/Si ratio than the equilibrium b phase.Lynch et al.found by X-ray microanalysis evidence for a ratio of Mg/Si in the b 'rods in an overaged material to be about 1.73[11],while Matsuma et al.[12]later determined the ratio to be about 1.68.For materials with excess silicon relative to Al±Mg 2Si there may be very small precipitates also of the b 'and a so-called B 'phase that is richer in silicon,or even Si particles [4].Because of this such particles with sizes comparable to b 0[7,4]may be mistaken for the b 0phase.The b 'and the B 'phase are reported as having the hexa-gonal unit cells a =0.705nm,c =0.405nm and a =0.104nm,c =0.405nm,respectively.In Refs [7,4]the relative number of b 0as compared with the smallest b '(and B ')particles was not deter-mined.It was recently suggested that b 'is a h.c.p.structure with a =0.405nm,c =0.67nm [12,13].1.2.4.The b phase.The b phase is the equilibrium phase in this system.It is the only phase up to now with a known structure.It is a CaF 2type f.c.c.structure with a =0.639nm having formula Mg 2Si.The structure may be described as strings of three atoms,Mg±Si±Mg,on the corners and faces of a cube,directed along the diagonals.Table 1.The evolution of Mg±Si phases near the quasi-binary section Al±Mg 2Si (top to bottom)Transformation/precipitation sequence Crystal type Size (nm)Composition Clusters of Si and fewer of Mg unknown unknown Si (Mg)Clusters containing Si and Mg unknown unknown Mg/Si <1Coherent spherical GP-I zonesunknown H 1±3Mg/Si H 1Semi-coherent GP-II zones (b 0needles)monoclinic H 4Â4Â50Mg/Si r 1b 'rods (and B 'rods)hexagonal H 20Â20Â500Mg/Si H 1.7b -Mg 2Si platescubicmicronsMg/Si =2The B 'phase is observed with alloys having excess Si relative to Al±Mg 2Si.It contains more Si than b '[4].ANDERSEN et al.:Al±Mg±Si ALLOY32841.3.SummationSumming up the information above,it appears that the phases that evolve from the very®ne Si-clusters into coarser particles take up progressively more magnesium during the coarsening and trans-formation processes,until an equilibrium compo-sition Mg2Si for the b phase®nally is reached.In this paper we report the structure determi-nation of the b0phase,which must be one of the important hardening phases in the commercial6xxx alloys.The technique used in the structure determi-nation is the through focus exit wave reconstruction technique in high resolution electron microscopy,in combination with quantitative electron di raction.2.EXPERIMENTAL2.1.Material and sample preparationThe as-received material was in the shape of extruded sections.It was supplied by HYDRO Aluminium AS(Sunndalsùra).The composition of the material was Al±0.2Fe±0.5Mg±0.53Si±0.01Mn (wt%).The material is from the same batch and extruded sections as investigated in Refs[10,14], there labelled as A and C,respectively.Specimen preparation and location in the extruded section of the samples for TEM are described in Refs[10,14]. Prior to the arti®cial ageing(5h at1858)the ma-terial had undergone a rather standard processing for an extrusion product.After the jet-polishing, specimens were stored in methanol.Most of the TEM experiments were performed within a day after specimen preparation.2.2.TEM equipment and experimental dataAll TEM work was performed using a PHILIPS CM30-ST/FEG electron microscope operated at 300kV.The microscope is equipped with a Photometrix1024Â1024slow scan CCD camera (12bits dynamical range),enabling a linear record-ing of HREM and ED puter control of the CCD camera and the microscope is handled with a Tietz software package.In this way series of 15±20HREM images with focus increments of typi-cally 5.2nm were recorded for each exit wave reconstruction.For the high resolution work suitable aluminium grains were selected and tilted into a h100i zone axis.HREM images were recorded at room tem-perature on as thin areas as possible,typically4±10nm.Needles were selected that could be viewed along their[010]zone axis.In this situation,the needles usually extend through the whole thickness of the specimen,such that no image blurring occurs due to overlap with the matrix.For a single image, the exposure time was usually about1s.For the di raction experiments a small spot-size (5±10nm)was used with exposure times of1±5s. Two zone-axes of the needles were chosen;[010]and[001].For the latter,the aluminium grain was tilted to a h310i zone axis,where statistically one out of six needles is in the correct orientation. Many of the needles contain stacking-faults or sec-ond phases.For a reliable structure determination it is important that the area where a di raction pat-tern is taken is free of defects.Given the resolution of the microscope it should be relatively easy to select single crystalline b0particles.However,to prevent the rapid contamination of the illuminated area that is typical for this kind of specimen at room temperature,the specimen was cooled to about100K.The sample cooling holder has a much poorer mechanical stability resulting in such a loss of resolution that selection of single crystal b0particles was di cult.Because of this ED pat-terns were taken from each particle encountered. Therefore quite many di raction patterns had to be discarded because of streaking and twinning prob-ably caused by the stacking-faults or sometimes extra spots caused by a intergrown phase that was determined to be b'.Five[010]di raction patterns were selected.For the[001]zone axis there is a greater chance of``cross-talk''due to more overlap of the matrix with the crystal,and suitable di rac-tion patterns for the re®nement were more di cult to®nd.Here®ve of the16recorded patterns were from the correct projection or particle.Only two of these patterns could later be re®ned.In addition to the problem with overlap spots from the b'phase, the reason was also the strong interference with the aluminium matrix in this projection that made sub-traction of the background di cult.The thickness of the investigated areas were somewhat larger for the di raction experiments than for the HREM ex-periments.The subsequent re®nements showed that the thickness usually exceeded10nm.In Fig.6, parts of two of the digitally recorded di raction images are shown.This®gure also shows some streaking caused by oversaturation of the CCD camera,which was not equipped with over¯ow pro-tection.The streaks and the aluminium di raction re¯ections were excluded from the images prior to data reduction.The exit wave reconstruction of the HREM focus series were done with a software package based on algorithms developed by Van Dyck and Coene[15±17].Given the coherency of the presently available ®eld emission guns the structural information in ordinary HREM images goes well beyond the point-to-point resolution in the electron microscope. The reconstruction method takes advantage of the knowledge about the transfer function,e.g.how the microscope optics distorts the electron wave after leaving the crystal(the exit wave)on its way to the image plane.This distortion is also a function of defocus.A series of HREM images are recorded at intervals of known defocus.The amplitude and phase information that is mixed up in the HREM images is retrieved through digital processing,andANDERSEN et al.:Al±Mg±Si ALLOY3285corrections for focus and spherical aberration are done.Furthermore,since typically15±20images are used in the reconstruction a considerable reduction in noise is attained.The exit wave is thus independent of various aberrations of the electron microscope, but it is still dependent on the specimen thickness. Only for very small specimen thicknesses is the exit wave very similar to the projected potential,viz.the projected atomic structure.For thicker sections,e.g. more than about10nm for the presently presented exit wave image,the local contrast in the exit wave can be quite di erent from the local scattering poten-tial.Thus,for such thicknesses a higher brightness at a certain point in the phase image of the exit wave as compared to other points,does not have to imply the presence of a locally more strongly scattering atom at this point.The good news is that the positions of the bright dots should correlate well with the location of the atoms.In the presently used electron microscope the res-olution is enhanced from0.20nm to about0.14nm. The HREM images presented in this work are recombined exit wave phase images.See Coene et al.[17],Zandbergen et al.[18]and Op de Beeck et al.[19]for examples and discussion of the method. The re®nement of the structure was done using the computer programme package MSLS[20].The CCD images with the di raction patterns were cor-rected for the¯at®eld(variation in the pixel sensi-tivity)and over¯ow during read-out of the CCD camera.Spurious X-ray signals and the Al di rac-tion spots were omitted.Automatic indexing and data reduction on the patterns were done.The obtained two-dimensional indices of the images were next transformed into the correct hkl indices so that the di raction data sets could be combined. MSLS was used for re®nement of the trial structure coordinates as obtained from the reconstructed exit wave.This program re®nes coordinates based on the least-squares procedure using the multi-slice al-gorithm to account for the dynamic di raction.The parameters re®ned were the thickness,the scaling factor,the centre of the Laue circle for each of the data sets,and the atomic coordinates and tempera-ture factors.The R-value used as measure of the correctness of the structure is de®ned as R=a(I calcÀI obs)2/a(I obs)2.Only the signi®cant re¯ections(I obs>2s(I obs))were used.R-values between2and6%are being quoted for the most reliably determined structures.3.RESULTS/DISCUSSION3.1.Conventional HREM/TEMConventional TEM shows the interior of the Al grains to mainly contain particles having a®ne nee-dle shape.The needles lay along h100i Al directions. Figure1gives an example.It is a bright®eld image in an Al h100i zone axis where the needles clearly point in two normal directions.The dark spots are needles pointing in the viewing direction.The exper-imental di raction patterns as well as HREM images show that the needle shaped particles mostly are of one kind,the monoclinic phase that is usually referred to as the b0phase.Figure2shows a HREM image with one such needle.Such images show the precipitates to be coherent along the nee-dle direction(their b-axis)with a h100i Al direction. This con®rms that their cell parameter is the same as aluminium,b=0.405nm.Many of the b0precipitates were found to con-tain stacking faults.In some precipitates an inter-growth of b0with another phase was observed.It is most probably the b'phase which has the hexago-nal axis along the needle direction.Sometimes this phase was found to exist alone.The cell parameter a=0.705nm has been con®rmed from exit wave simulated images.These images will be published later.In the same material coarser rods of the b' phase have earlier been investigated;It was reported that they nucleate on®ne Al±Fe±Si particles[14].It may be expected that much of the b'particles nucle-ate on b0since with longer arti®cial ageing times the micro-structure will contain an increasing amount of rods of b'.By selected area electron dif-fraction the coarse b'phase in this material was determined to have a hexagonal structure with a H0.71nm,c H0.41nm.The a-axis therefore®ts well with the phase intergrown with b0.The struc-ture of the small and large b'is therefore probably the same.We did not observe any B'phase in the material.3.2.Elemental analysis of the b0phaseWe performed several X-ray analyses of the small precipitates with the spot along the needle axis. Due to the very thin specimen areas(10±40nm)the spectra obtained should in principle not be signi®-cantly in¯uenced by absorption in the specimen, which is the most important reason for deviations from the actual concentration.In spite of the small size of the spot(1±2nm),there was always an Al peak present in the spectrum,of varying height. This is partly caused by stray electrons travelling down the column of the electron microscope which are not focused with the rest of the electrons in the beam probe and therefore many hit aluminium. Secondly,because during analysis the beam is par-allel to the needle axis,i.e.to the[010]zone axis of b0,this implies an e ective beam broadening by the elastic scattering of some electrons into aluminium. For some of the recordings there is also an e ect of specimen drift during recording.Another e ect is the contamination layer and the(aluminium)oxide layer on the surface of the particle which primarily contains Al.The EDS experiments could therefore not rule out that some Al is contained in the precipitate.As a standard for determining the K-ratios a mineral forsterite was used whose mainANDERSEN et al.:Al±Mg±Si ALLOY 3286components are MgO and SiO 2with a composition so that the Mg/Si atomic ratio is 2.Not taking into account the possible systematic deviations,the EDS experiments indicated that the atomic ratio for Mg/Si was close to or even below 1.The accuracy of these measurements were on the order of 10%.However,they ruled out the earlier accepted ratio of 2for the b 0phase.EDS measurements were also performed on larger particles of the b 'and b -Mg 2Si phases which had been extracted from the alu-minium matrix.These phases gave compositions near the expected,as listed in Table 1.The accuracy here was much better for thin sections since the alu-minium matrix could be avoided entirely.3.3.Exit wave reconstruction3.3.1.The unit cell.Coherency of the b 0phase with the matrix .In Fig.3a reconstructed exit wave (phase)of a b 0particle in the [010]orientation embedded in aluminium is shown.The b 0[010]direction is parallel to a h 100i type aluminium zone axis and is along the needle.Atomic columns in the viewing direction in the image appear as bright dots.The columns in the Al matrix are clearly resolved;in this projection the separation between nearest neighbor columns are 0.2025nm,or half the Al unit cell length.Due to the face centering of alu-minium the nearest neighbor atom columns are also shifted 0.2025nm in the viewing direction relative to each other.In the ®gure circles are drawn that indicate the two di erent height positions of the atoms in the viewing direction.The lattice image of the Al matrix changes over the image due to local variations in tilt.The b 0unit cell is outlined in the particle.Due to the C-centering,the a -axis is twice the apparent periodicity.By calibrating the magni®cation of the image using the aluminium lattice,the unit cell was established to be a =1.51620.002nm,c =0.67420.002nm and b H 105±1068.HREM of other nee-dles lying in the normal direction (Fig.2)have shown that there is a full coherence between the crystal along the b -axis with the same periodicity as the aluminium matrix;therefore b =0.405nm.In the re®nement of di raction images for this zone axis,the monoclinic angle is calculated.It was found to have a mean value b =105.320.58when averaged over 7di raction patterns.The b 0unit cell is closely related to the alu-minium lattice.From di raction patterns (Fig.5)asFig.1.A typical low magni®cation micrograph of b 0needles in a h 001i Al zone axis.Needles are directed along the three h 100i Al directions and appear therefore point-like (dark spots)in the viewing direction.The needles have a mean diameter of about 4nm,and an average length about 50nm.Alarger b 'rod (white appearance)is directed in the viewing direction in the centre of the image.ANDERSEN et al.:Al±Mg±Si ALLOY 3287well as from the exit wave (Fig.3)the following relationship between the phases can be found; 001 Al k 010 b 0,"310 Al k 001 b 0,230 Al k 100 b 0This relationship is the same as found earlier byEdwards et al.[7].A corresponding super cell in aluminium can be de®ned by real vectors ~ab 0 2~a Al 3~b Al ,~b b 0~c Al ,~c b 0 À32~a Al 12~b Alwith respective lengths 1.46,0.405and 0.64nm witha monoclinic angle of 105.38.Half of this super cellis outlined in Fig.3on the left side of the b 0par-ticle.The super cell is also C-centred monoclinicsince two neighbor corners of the half cell along ~ab 0fall on Al atoms in di erent layers.The unit cell for b 0is slightly larger than this Al super cell;3.8%along ~ab 0and 5.3%along ~c b 0.The half super cell (asymmetric unit)contains 11Al atoms.The coherency between b 0and aluminium aids in quantifying the shift of the stacking fault (sf)in the particle that is indicated in Fig.3;By using the Al matrix as reference it can be veri®ed that Al atoms at the left interface,at the upper part (e.g.near the white corners of the unit cell of b 0)are at a di er-ent height relative to similar atoms of b 0on the lower part (here with a black ®ll){.This is illus-trated by the two outlined (half)super cells in the Al matrix that are related to the unit cell of b 0in the upper and lower part of the particle.These super cells are shifted a vector a Al [101]/2relative to each other,which indicates that the shift across the stacking fault in the particle is nearly the same.This shift vector is a Burgers vector of the most common dislocation in aluminium.A model of the fault is given in Section5.Fig.2.Ordinary HREM image of b 0-needle in an h 001i zone axis in Al.The c -axis of the needle is in the plane,and the coherency with h 100i Al in the needle direction is evident.As expected,there is no exact zone axis of b 0along the viewing direction h 001i Al zone axis.The left part of the picture was fourier ®ltered;A high pass ®lter was applied to the upper part and a low pass ®lter to the lower partto extract the periodic information from Al (upper)and the b 0-phase (lower)only.{Alternatively,assume the corners of the outlined unit cells of b 0on each side of the stacking fault to be at thesame heights along ~cb 0.The atoms to the left of Ðand in the matrix outside Ðthese corners must then necessarily have similar heights,since the atomic con®guration and distances to the left of these corners are similar,whether above or below the stacking fault.This assumption must be wrong;When keeping track of the atomic columns in the matrix it leads to the conclusion of an Al atom being at two heights at the same time.Therefore,the corners ofthe unit cells along ~cb 0have di erent heights across the stacking fault.ANDERSEN et al.:Al±Mg±Si ALLOY3288In Fig.4the coherency between the two phases can be studied in more detail.This image is a Fast Fourier Transformation (FFT)of part of Fig.3.Only the lower part of the b 0precipitate is included to reduce streaking caused by the stacking fault.After applying a Fourier ®lter (selecting the con-tents inside the circles superposed on the FFT of Fig.4)the Al re¯ections plus the 610,610,403and 403re¯ections of b 0contribute to the image in Fig.5.The white arrows indicate interface dislo-cations between the particle and matrix.For example,the b 0(601)lattice planes with a spacing d 601=0.211nm are parallel with the Al (200)planes with a spacing of 0.203nm.Therefore,one interface dislocation is expected for each 25Al d 200spacings (normal to the [100]axis in the ®gure).Similarly,for the 403planes,for each 20Al d 020spacing one expects an interface dislocation.The spacings between dislocations observed in Fig.5are di erent from the theoretical ones.The reason for this devi-ation is probably variation in local strain in the particle caused by the stacking fault.Although the exact dislocation is not clear in the image,a matrix dislocation found (marked ``d '')also complicates the situation concerning the mis®t dislocations.This dislocation is found to have a Burgers vector b =0.5a Al [101],as was found when a Burgers vec-tor loop was performed around the particle.This is indicated by the open arrow (d).In Fig.6,two ex-perimental di raction images from the [010]and [001]zone axes are shown.The b 0610and 403re¯ections that coincide with the 200and 020Al matrix re¯ections can also be seen in Fig.6(a).In Fig.6(b)the perfect coherency relation of the (010)lattice planes of the b 0phases with (200)lattice planes can be seen from the overlap of the respect-ive di raction spots.3.3.2.Extraction of the atomic coordinates for b 0from the exit wave images .Figure 7(a)is an increased magni®cation of part of Fig.3.Here the atomic columns are represented as white dots.From this image the atomic positions were esti-mated using the following assumptions:(1)The number of atoms in the unit cell is 22,just as the number of atoms in the similar super cell in aluminium.The number ®ts the apparentnumberFig.3.Phase of an reconstructed exit wave of a typical b 0needle in Al is shown.The needle is viewed head-on along its [010]axis,and along an Al h 001i zone axis.Atomic columns appear white.The b 0unit cell and half the corresponding super cell in Al are outlined.Similarly ®lled circles in the matrix or in the precipitate are atoms (Al or Mg)at the same height.A stacking fault (sf)is indicated.The shiftacross the stacking fault can be determined to be a Al [101]/2.ANDERSEN et al.:Al±Mg±Si ALLOY 3289。

第42卷㊀第5期2021年5月发㊀光㊀学㊀报CHINESE JOURNAL OF LUMINESCENCEVol.42No.5May,2021㊀㊀收稿日期:2020-12-15;修订日期:2021-02-02㊀㊀基金项目:国家自然科学基金(51672167);西安市科技计划(201805027YD5CG11);陕西师范大学创新创业训练计划项目(S202010718057)资助Supported by National Natural Science Foundation of China(51672167);Science and Technology Project of Xi a n(201805027YD5CG11);Innovation and Entrepreneurship Training Program of Shaanxi Normal University(S202010718057)†共同贡献作者文章编号:1000-7032(2021)05-0642-08Ba 2+调制SrGe 4-x O 9ʒx Mn 4+晶体结构及其发光性质魏恒伟1,2†,李雅婷1†,凌钰婷1,林继周1,刘天用3,何地平2,焦㊀桓1∗(1.陕西师范大学,化学化工学院,陕西西安㊀710062;2.陕西师范大学,基础实验教学中心,陕西西安㊀710062;㊀3.烟台希尔德新材料有限公司,山东烟台㊀264006)摘要:采用传统固相法在1100ħ合成了SrGe 4-x O 9ʒx Mn 4+(SGOM)系列荧光粉,通过Ba 2+取代Sr 2+调制了荧光粉基质的局部结构,对样品的晶体结构㊁发光性质和热稳定性进行了探讨㊂XRD 测试结果表明,Mn 4+和Ba 2+均成功地掺杂进入基质SrGe 4O 9晶格,没有其他物相产生㊂在275nm 紫外光激发下,SGOM 荧光粉的发射光谱是位于600~750nm 的深红色谱带,峰值波长位于660nm,主要源于Mn 4+离子2E g ң4A 2g 能级跃迁的窄带发射,优化的Mn 4+浓度为0.015㊂利用Ba 2+离子对SrGe 3.985O 9ʒ0.015Mn 4+荧光粉的发光性质进行调控,发现随着Ba 2+浓度增大,发射光谱的强度先上升后下降,最佳Ba 2+浓度为0.4㊂Ba 2+离子的引入造成基质结构中Sr1O10多面体产生局部扩张,导致样品的发射光谱展宽㊂为了解决封装白光LED 中有机材料存在的难以承受发热的问题,制备出了基于SrGe 3.985O 9ʒ0.015Mn 4+荧光粉的荧光玻璃㊂优良的发光性质和热稳定性使SGOM 荧光粉具备了应用于白光LED 器件的前景㊂关㊀键㊀词:晶体结构;SGOM 荧光粉;Ba 2+调制;荧光玻璃中图分类号:O482.31㊀㊀㊀文献标识码:A㊀㊀㊀DOI :10.37188/CJL.20200386Crystal Structure and Luminescent Properties of Ba 2+Modulated SrGe 4-x O 9ʒx Mn 4+PhosphorsWEI Heng-wei 1,2†,LI Ya-ting 1†,LING Yu-ting 1,LIN Ji-zhou 1,LIU Tian-yong 3,HE Di-ping 2,JIAO Huan 1∗(1.School of Chemistry &Chemical Engineering ,Shaanxi Normal University ,Xi an 710062,China ;2.Basic Experiment Center ,Shaanxi Normal University ,Xi an 710062,China ;3.Shield Advanced Material Technology Company ,Yantai 264006,China.)∗Corresponding Author ,E-mail :jiaohuan @Abstract :A series of SrGe 4-x O 9ʒx Mn 4+(SGOM)phosphors were prepared at 1100ħby traditionalsolid-state method.The crystal structure,luminescent properties and temperature-dependent of SGOM were investigated.Local structure of SrGe 4O 9(SGO)was modulated by the introducing of Ba 2+ions.The results of XRD showed that both Mn 4+and Ba 2+ions were successfully doped into the SGO,and no otherimpurity phase was detected.Fluorescent measurement indicates that SGOM phosphors produce red emis-sion(600~750nm)upon UV(275nm)light excitation,which can be attributed to 2E g ң4A 2g of Mn 4+.The optimal Mn 4+concentration in these phosphors equals 0.015.The emission spectra of SrGe 3.985O 9ʒ0.015Mn 4+was tuned by the introducing of Ba 2+ions.The luminescent intensity of SGOM was improved㊀第5期魏恒伟,等:Ba2+调制SrGe4-x O9ʒx Mn4+晶体结构及其发光性质643㊀up to50%when the Ba2+doping concentration is0.4,and an emission spectra broadening was also ob-served.This phenomenon is thought to be originated from the expanding of the local structure of Sr1O10 polyhedron caused by the Ba2+doping.The phosphor-in-glass(PiG)technique was used to explore the properties of SGOM phosphor to overcome the decomposing issue of the organic materials.These phos-phors exhibit potential application in WLED.Key words:crystal structure;SGOM phosphors;Ba2+modulated;phosphor in glass1㊀引㊀㊀言白光LED作为固态照明光源具有高流明效率㊁低能耗㊁长使用寿命以及环境友好等优点,被广泛应用于显示与照明领域[1-3]㊂但由于目前普遍采取的方案中缺少红光成分[4-6],导致封装的灯具存在显色指数低㊁色温高等问题㊂寻找合适的红色荧光粉是解决这一问题的关键所在㊂荧光材料通常以氧化物㊁硫化物㊁氟化物以及氮化物作为基质材料,将稀土离子(Eu2+㊁Ce3+)或过渡区金属离子(Mn4+㊁Bi3+㊁Cr3+)引入基质产生不同波长的发光[7-12]㊂以Eu2+为激活剂获得红色荧光粉的发射光谱半峰宽大,合成条件(还原性气氛)苛刻㊂例如,Schnick等[13]合成的Sr2[BeAl3N4]ʒEu2+红色荧光粉,Sohn等[9]发现的新型Ba2-x-LiAlS4ʒEu2+荧光粉,在应用过程中没有明显优势㊂由于Mn4+离子的2E gң4A2g能级跃迁可产生窄带的红光发射,掺杂到氧化物(铝酸盐和锗酸盐)㊁氟(氧)化物等基质中,可得到发射光谱范围为600~ 750nm的红色光发射的荧光粉,而以Mn4+为激活剂的窄带红粉在发光特性上可以满足LED照明器件的要求㊂但制备过程中大多使用氢氟酸,对环境造成了污染㊂例如,陈学元等[14]报道了非稀土掺杂的红色发光的K2SiF6ʒMn4+荧光粉,焦桓等[15]报道了发射红光的K3TaO2F4ʒMn4+荧光粉㊂因而研究人员对于氧化物基质的窄带红粉寄予了希望㊂彭明营等[16]发现了具有红光发射的Sr4Al12O25ʒMn4+荧光粉,尤洪鹏等[17]介绍了CaAl12O19ʒMn4+红色荧光粉,这些荧光粉性能优良,但是存在合成条件苛刻㊁热稳定性有待改进等问题㊂与铝酸盐相比,锗酸盐的合成条件比较温和,有可能获得具有红色光的发光材料㊂胡义华等[7-8]报道了SrGe4O9ʒMn4+和BaGe4O9ʒMn4+红色荧光粉㊂Park等[18]初步研究了Sr1-x Ba x-Ge4O9ʒ0.005Mn4+(0.00ɤxɤ1.00)荧光粉的发光,但未对基质局部结构与发光性能间的关系进行细致的分析,调控不系统㊂结构调控是发光性质调整的重要途径,因而本文选取SrGe4O9为基质材料,详细研究了Mn4+掺杂SrGe4O9和Ba2+调制SrGe4-x O9ʒx Mn4+荧光粉的晶体结构与发光性质之间的关系㊂通过Rietveld方法对基质的X射线衍射数据进行精修,分析晶体结构的局部变化对发光性质的影响,进一步讨论发射光谱展宽的原因㊂为了克服传统封装白光LED过程中有机材料存在的问题,将所合成发光强度最高的样品与二氧化硅玻璃粉相结合,制备出了荧光玻璃,并测试其基本性能㊂该荧光粉具有紫外激发㊁红色发射的性能,具备了应用于白光LED器件的基本条件㊂2㊀实㊀㊀验2.1㊀样品合成采用传统固相法制备了Sr1-y Ge4-x O9ʒx Mn4+, y Ba2+(x=0.0~0.03;y=0.0~0.6)系列荧光粉㊂按化学计量比称取如下实验原料:BaCO3(AR)㊁SrCO3(AR)㊁GeO2(AR)和MnCO3(AR)㊂将称取的原料置于玛瑙研钵中,加入少量无水乙醇研磨30min,混和均匀后装入Al2O3坩埚㊂将装有样品的坩埚在箱式烧结炉中于1100ħ烧结6h,而后随炉冷却至室温,研磨得粉末状样品㊂荧光玻璃的制备:将选取的荧光粉与二氧化硅玻璃粉(24.58SiO2-1.25Al2O3-1.48NaCO3-0.25BaCO3-0.60KCO3-11.33H3BO3)按一定比例放入粉体混合机(GH-5,上海振春粉体设备有限公司)中进行研磨,利用冷等静压机(LDJ630/3000-300S)将混匀的原料压制成型后,装入Al2O3坩埚,置于箱式电阻炉(SX-4-10,北京科伟永兴仪器有限公司)中进行烧结㊂程序结束后,自然降温至室温取样并进行表征㊂2.2㊀样品测试表征利用MiNiFlex600型X射线衍射仪(XRD)对合成的样品进行物相表征,辐射源为Cu Kα靶(λ= 0.15406nm),工作条件为40kV和15mA,步长644㊀发㊀㊀光㊀㊀学㊀㊀报第42卷0.02ʎ,扫速分别为2(ʎ)/min 和10(ʎ)/min,数据收集范围2θ=10ʎ~80ʎ㊂采用日本HITACHI F-4600荧光光谱仪结合热猝灭分析仪(TAP-02)对样品的光谱和热稳定性进行测试和记录,光源为450W Xe 灯,光电倍增管电压400V,入射和出射狭缝为5nm,扫描速率240nm/min㊂使用FLS-980稳态瞬态光谱仪(英国爱丁堡公司)测试样品的荧光寿命,激发波长为275nm,发射波长为660nm,光源为微秒灯㊂利用紫外-可见近红外光谱仪(Lambd 1050,美国Perkin-Elmer 公司)测试荧光玻璃片的透射光谱㊂3㊀结果与讨论3.1㊀SrGe 4O 9物相和结构图1为SrGe 4O 9粉末X 射线衍射图和晶体结构示意图,通过对基质的XRD 进行Rietveld 精修拟合(如图1),本文所合成SrGe 4O 9的晶胞参数为a =b =1.13580nm,c =0.47607nm,V cell =0.5318753nm 3,Z =3,该数据与Fumito Nishi 报道基本一致[19]㊂详细的晶体学参数见表1,结构中原子的位置㊁占有率以及温度因子见表2㊂图1内插图为沿[001]方向SrGe 4O 9的晶体结构示意图㊂红色圆球为Sr 2+离子,蓝色圆球为Ge 4+离子,青蓝色圆球为O 2-离子㊂SrGe 4O 9晶体结构的空间群为P 321(No.150)㊂该结构具有特征的三次轴,Ge1O6和Ge2O6八面体分别与Ge3O4和Ge4O4四面体共顶点连接,形成基质的骨架结构㊂Sr 2+离子填充于孔道之间,形成Sr1O10多面体,平衡结构中的电荷,维持结构稳定㊂202兹/（°）I n t e n s i t y /c o u n t s100000800006000040000200000-1000010304050607080Sr1Sr1Sr1Sr1Sr1Sr1Ge3Ge1Ge3Ge3Ge4Ge2Ge2Ge4Ge4Ge4Ge4Ge4acb 图1㊀Rietveld 精修拟合SrGe 4O 9的X 射线衍射图谱(蓝圈:观察点;红线:计算点;黑线:误差),内插图:沿[001]方向SrGe 4O 9的晶体结构示意图㊂Fig.1㊀Observed(blue dots)and calculated(red line)powder XRD patterns as well as difference profile(black line)for the Ri-etveld structure analysis of SrGe 4O 9.Inset:crystal structure of SrGe 4O 9along [001].表1㊀SrGe 4O 9Rietveld 精修XRD 的晶体学参数Tab.1㊀Crystallographic data of SrGe 4O 9derived from Rietveld refinement of powder XRD dataFormulaCrystal system Space groupRadiationLatticeparameters a /nmc /nmV cell /nm 3Formula unit per cell,ZSrGe 4O 9TrigonalP 321(No.150)Cu Kα11.135800.476070.53187533FormulaStructurerefinementT /KProfile rangeNumber ofdata ProfilefuncationR exp /%R wp /%R p /%GOFSrGe 4O 9Topas 29310ʎ~80ʎ7002PV_MOD2.327.855.653.38表2㊀结构精修获得的SrGe 4O 9原子位置、占有率和温度因子Tab.2㊀Atomic coordinates,site occupancies and temperature factors for SrGe 4O 9determined by Rietveld refinement on powderXRD dataSiteNp.xyz Atom.Occ.B eq .Sr13e 0.328000.000000.00000Sr 2+11Ge11a 0.00000.00000.0000Ge 4+11Ge22d0.333330.666670.10760Ge 4+11Ge33f0.820900.00000.50000Ge 4+11㊀第5期魏恒伟,等:Ba 2+调制SrGe 4-x O 9ʒx Mn 4+晶体结构及其发光性质645㊀表2(续)SiteNp.xyz Atom.Occ.B eq .Ge46g 0.490800.341000.39900Ge 4+11O13f0.511200.000000.50000O 2-11O26g 0.602200.422200.12450O 2-11O36g 0.154600.061600.76360O 2-11O46g 0.325500.214500.29490O 2-11O56g 0.510200.249600.67220O 2-113.2㊀SrGe 4-x O 9ʒx Mn 4+荧光粉的物相分析图2为SrGe 4-x O 9ʒx Mn 4+(x =0.002~0.030)系列荧光粉的X 射线衍射图谱㊂所合成样品的XRD 谱线均与PDF No.14-0029标准卡片一致,无杂峰出现,即所得样品均为纯相SrGe 4O 9㊂在六配位的环境中,Ge 4+(r Ge =0.053nm)与Mn 4+离子半径(r Mn =0.053nm )相等㊂当向基质SrGe 4O 9中引入Mn 4+离子时,Mn 4+取代Ge 4+进入晶格,不会对基质结构产生影响㊂20602θ/（°）I n t e n s i t y /a .u .SrGe 4-x O 9∶x Mn 4-10304050PDF No.14鄄0029x =0.002x =0.005x =0.010x =0.015x =0.020x =0.025x =0.030图2㊀SrGe 4-x O 9ʒx Mn 4+荧光粉的X 射线衍射图谱Fig.2㊀XRD pattern of SrGe 4-x O 9ʒx Mn 4+phosphor3.3㊀SrGe 4-x O 9ʒx Mn 4+荧光粉的发光性质对SrGe 4-x O 9ʒx Mn 4+(x =0.002~0.030)系列荧光粉的发光性能进行了测试,结果如图3所示㊂图3(a)为选取样品(x =0.015)的激发和发射光谱㊂由图可知,检测波长为660nm 时,样品的激发光谱为位于200~520nm 的宽带,包含两个明显的激发峰,分别位于275nm 和430nm㊂前者源于4A 2ң4T 1跃迁,后者为4A 2ң4T 2跃迁㊂采用275nm 紫外和430nm 蓝光分别对样品进行激发,发射光谱均位于660nm,光谱范围为600~750nm,可归属为Mn 4+3d 3电子层间2E 2g ң4A 2g 之间的跃迁,这与胡义华等[8]报道的结果基本一致,表明该类荧光粉与紫外芯片和蓝光芯片可以很好地匹配㊂图3(b)为275nm 和430nm 激发系列样品的发光强度随x 的变化趋势图㊂其中以275nm 紫外光激发时,样品的发射强度较高,是以430nm 蓝光激发发射强度的6倍㊂随着x 值增加,样品的发光强度上升,当x =0.015时达到最大,而后由于浓度猝灭现象的产生导致发光强度下降㊂0.8300700姿/nmN o r m a l i z e d i n t e n s i t y姿ex =430nm姿ex =275nm EM200400500600650750EX1.00.60.40.20（a ）姿em =660nmSrGe 3.985O 9∶0.015Mn 4+0.300Mn 4+content xI n t e n s i t y /a .u .姿ex =430nm0.02030000800060000（b ）400005000040002000姿ex =275nm 0.0250.0150.0100.0050图3㊀(a)选取样品SrGe 3.985O 9ʒ0.015Mn 4+的归一化激发㊁发射光谱;(b)SrGe 4-x O 9ʒx Mn 4+(x =0.002~0.030)发射光谱强度变化㊂Fig.3㊀(a)Normalized excitation (EX)and emission (EM)spectra of the selected SrGe 3.985O 9ʒ0.015Mn 4+.(b)Dependence of the PL intensity on the Mn 4+content xin the SrGe 4-x O 9ʒx Mn 4+(x =0.002-0.030)system.3.4㊀Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+荧光粉的物相及发光性质阴阳离子取代是对荧光粉的发光性能进行改进和调控的常用手段[20]㊂基于SrGe 3.985O 9ʒ0.015Mn 4+荧光粉,本文以Ba 2+取代基质中的Sr 2+㊂当一部分Ba 2+进入Sr 2+格位后,Sr1O10多面体转变为(Sr1/646㊀发㊀㊀光㊀㊀学㊀㊀报第42卷Ba)O10多面体,Ba 2+离子半径(r Ba =0.0135nm)大于Sr 2+离子半径(r Sr =0.0118nm),致使GeO6和GeO4局部环境产生变化㊂由于Mn 4+对配位环境的变化非常敏感[14],故可实现对其发光性能的调控㊂图4(a)是Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+系列荧光粉的XRD㊂观察可知随着Ba 2+含量y 值的增加,样品的所有衍射峰与标准卡片相吻合,表明Ba 2+成功地取代了部分Sr 2+,基质结构并未发生改变㊂通过对系列样品的仔细分析,发现衍射峰(111)随y 值增大逐渐宽化,说明Ba 2+浓度升高会导致样品的结晶性降低㊂对所得样品的XRD 进行Rietveld 精修拟合,其晶胞参数的变化如图4(b)所示㊂a 随着y 值上升从1.1358nm 增大到1.1524nm;c 为0.4753nm,基本不受y 值影响;晶胞体积V cell 呈上升趋势,由0.531875nm 3增大到0.546618nm 3,进一步证明Ba 2+进入了基质结构㊂10502兹/（°）I n t e n s i t y /a .u .60403020PDF No.14鄄0029x =0x =0.10x =0.20x =0.30x =0.40x =0.50x =0.60(111)24252兹/（°）（a ）Sr 1-y Ge 3.985O 9∶0.015Mn 4+,y Ba 2+0.4Ba2+content ya a n d c /n m0.30.20（b ）Sr 1-y Ge 3.985O 9∶0.015Mn 4+,y Ba 2+c0.51.161.171.151.141.131.120.4950.4800.4650.10.6V cell 0.5320.53６0.5４０0.5４４0.5４８Ｖc e l l /n m 3a 图4㊀(a)Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+(y =0.0~0.6)荧光粉的XRD 谱图;(b)晶胞参数a ㊁c 和V cell随Ba 2+浓度的变化㊂Fig.4㊀(a)XRD patterns of Sr 1-y Ge 3.985O 9ʒ0.015Mn4+,y Ba 2+(y =0.0~0.6)phosphor.(b)Cell parametera ,c and V cell varied with Ba 2+concentration.图5(a)是Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+系列荧光粉的发光强度变化㊂随Ba 2+含量y 值增大,样品的发光强度不断上升;当y =0.4时,发光强度达到最大,较未掺杂样品的发光强度提升约50%;当y >0.4时,发光强度开始下降㊂结合衍射数据(图4(b)),可以发现随Ba 2+浓度增大,尽管样品的衍射峰位和数量没有变化,但衍射峰出现宽化,表明样品的结晶性降低,导致荧光粉发光强度降低㊂为了体现Ba 2+离子对荧光粉发射光谱的调制作用,给出了样品归一化的发射光谱,如图5(b)所示㊂样品在275nm 紫外光激发下产生红光发射,P1(642nm)㊁P2(655nm)㊁P3(665nm)和P4(670nm)主要源于Mn 4+进入GeO6八面体形成MnO6,导致2E g 和2T 2g ң4A 2g 跃迁发射自旋和宇称双重禁阻[7,21]㊂随着Ba 2+的引入,主峰位(660nm)基本上没有移动,样品发射光谱的峰形展宽,这是由于Ba 2+含量增加,基质晶格扩张,使P1㊁P2㊁P3和P4峰位处的相对强度发生变化㊂由文献[22]可知,SrGe 4O 9ʒMn 4+和BaGe 4O 9ʒMn 4+荧光粉的发射光谱存在明显差异,前者的发射光谱与本文基本一致,后者的发射光谱包含两个强度相当的峰位(P2和P3)㊂因此我们推断,系列样品中Sr 2+逐渐被Ba 2+取代至Sr 2+ʒBa 2+比值等于2ʒ3时,发射0.800.6Ba 2+content yN o r m a l i z e d i n t e n s i t y1.00.60.40.20（a ）0.10.20.30.40.5y =0.4Sr 1-y Ge 3.985O 9∶0.015Mn 4+,y Ba 2+600姿/nmN o r m a l i z e d i n t e n s i t y1.20.60.40.20（b ）650P11.41.00.8P4P3P2670nm 642nm EM 姿ex=275nm 655nm665nm 700750Sr 1-y Ge 3.985O 9∶0.015Mn 4+,y Ba 2+y =0.000.100.200.300.400.500.60图5㊀(a)Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+(y =0.0~0.6)荧光粉的归一化发射光谱强度变化;(b)系列样品的归一化发射光谱㊂Fig.5㊀(a)Normalized PL intensity on the Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+(y =0.0~0.6).(b)Normalizedemission spectra of the series samples.㊀第5期魏恒伟,等:Ba 2+调制SrGe 4-x O 9ʒx Mn 4+晶体结构及其发光性质647㊀峰位P2ʒP3处发射强度的比值趋近于1ʒ1,导致系列样品的发射光谱的峰形由以SrGe 4O 9ʒMn 4+为主渐变为文献中以BaGe 4O 9ʒMn 4+为主㊂为了进一步分析局部结构变化对Mn4+周围配位环境的影响,本文将SrGe 4O 9结构中的Sr1O10多面体与BaGe 4O 9结构中Ba1O10多面体的键长进行了对比,相关数据如表3所示[19,23]㊂可以看出,Sr O 键长均小于Ba O 键长,这就意味着Ba 2+进入SGOM 荧光粉的结构中后,会使Sr1O10多面体扩张形成(Sr1/Ba)O10,进而影响与之相连接的(Ge /Mn)O4和(Ge /Mn)O6多面体,使Mn4+周围的配位环境受到挤压,导致Mn4+离子间距离缩短,相互作用增加,无辐射跃迁减少,从而提高了材料的发光强度,并减少了热衰㊂表3㊀Sr1O10和Ba1O10多面体局部晶体结构(键长)的对比[19,23]Tab.3㊀Local structure of Sr1O10polyhedron compare withBa1O10polyhedron [19,23]abc Sr1O10多面体ab cBa1O10多面体名称键长/nm名称键长/nmSr1 O10.3156(9)Ba1 O10.3223(1)Sr -O20.2601(8)Ba1 O20.2708(1)Sr1 O50.2977(7)Ba1 O50.3029(7)Sr1 O40.2820(7)Ba1 O40.2896(1)Sr1 O30.2644(8)Ba1 O30.2765(4)图6是Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+系列荧光粉寿命的归一化图谱,内插图反映了样品荧光寿命随Ba 2+含量y 的变化趋势㊂样品的荧光寿命曲线可用单指数函数[24]进行拟合,方程式如下:I t =A 1exp(-t /τ),(1)其中,I t 是在时间t 对应的发光强度,A 1是常数,τ是寿命㊂计算发现Ba 2+含量y 值增加到0.6时,样品的寿命呈线性增加趋势,从1.003ms 增加到1.384ms㊂这可能是由于(Sr1/Ba)O10多面体扭曲改变Mn4+周围的局部环境,增大了跃迁几率,减少了非辐射跃迁的几率[25]所致㊂荧光粉的热稳定性是材料应用的一个重要指104t /msN o r m a l i z e d i n t e n s i t y1230.110姿ex =275nm,姿em =660nmy=0.00.10.20.30.40.50.6Sr 1-y Ge 3.985O 9∶0.015Mn 4+,y Ba 2+1.41.31.21.11.000.10.20.30.40.50.6Ba 2+content yt /m s图6㊀Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+(y =0.0~0.6)荧光粉的归一化寿命曲线和寿命-浓度变化曲线Fig.6㊀Normalized decay curves and the correlation of life-time-concentration of Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+(y =0.0-0.6)phosphor标,主要依赖于材料发光强度与温度之间的变化关系㊂图7为Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+系列化合物中y =0和y =0.4荧光粉样品发光强度随温度的变化趋势图㊂随着温度升高,SrGe 3.985O 9ʒ0.015Mn 4+和Sr 0.6Ba 0.4Ge 3.985O 9ʒ0.015Mn 4+样品的发光强度均呈下降趋势,150ħ的发光强度较室温测试强度分别衰减了24.5%和29.1%,表明两者的热稳定性良好㊂对比两者发现,Ba 2+离子的引入不仅将Sr 0.6Ba 0.4Ge 3.985O 9ʒ0.015Mn 4+样品的发光强度提高了近50%,还明显改善了其热猝灭效应,与前面通过分析表3数据得出来的结果基本一致㊂传统LED 封装主要采用 蓝光芯片+硅胶树脂+荧光粉 的方式,得到的产品存在严重的光衰㊁光色偏移㊁光密度低等问题[26]㊂为了解决这一问题, 蓝光芯片(紫外芯片)+荧光玻璃片(荧光陶瓷片) 的方式应运而生[27-30]㊂本文对得到的荧光粉进2.5×10525225T /℃I n t e n s i t y /a .u .50751001251501752002503.0×1052.0×1051.5×1051.0×1055.0×1040y =0.00.4Sr 1-y Ge 3.985O 9∶0.015Mn 4+,y Ba 2+图7㊀样品Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+(y =0,0.4)的发光强度随温度的变化Fig.7㊀PL intensity varied with temperature in the selectedsample Sr 1-y Ge 3.985O 9ʒ0.015Mn 4+,y Ba 2+(y =0,0.4)648㊀发㊀㊀光㊀㊀学㊀㊀报第42卷行玻璃化处理,制备出了厚度为0.2mm 的荧光玻璃片㊂图8是样品Sr 0.6Ge 3.985O 9ʒ0.015Mn 4+,0.4Ba 2+10090200700姿/nmT r a n s m i t t a n c e /%8070605040300400500600800UVSr 0.6Ge 3.985O 9∶0.015Mn 4+,0.4Ba2+图8㊀Sr 0.6Ge 3.985O 9ʒ0.015Mn 4+,0.4Ba 2+荧光玻璃的透射光谱Fig.8㊀Transmittance spectrum of Sr 0.6Ge 3.985O 9ʒ0.015Mn 4+,0.4Ba 2+所制备荧光玻璃的透射光谱,可以看到其在275nm 和430nm 均有吸收,这与图4(a)中的激发光谱一致㊂在550~800nm 范围内,样品的最大透光率为78.7%㊂由内插图可知,在紫外灯照射下,样品呈现红光㊂4㊀结㊀㊀论本文利用高温固相法合成了系列SrGe 4-x O 9ʒx Mn 4+(SGOM)红色荧光粉,通过向基质中引入Ba 2+调制基质的局部结构,增加了电子与声子之间的相互作用,实现了Mn 4+离子发射光谱的调控㊁发光强度的增强,并减弱了其热猝灭效应㊂将荧光粉和玻璃相结合,获得了最大透光率为78.7%㊁厚度为0.2mm 的荧光玻璃,拓展了荧光粉在白光LED 中的应用㊂参㊀考㊀文㊀献:[1]PARK K ,HEO M H ,KIM K Y ,et al ..Photoluminescence properties of nano-sized (Y 0.5Gd 0.5)PO 4ʒEu 3+phosphor pow-ders synthesized by solution combustion method [J ].Powder Technol .,2013,237:102-106.[2]SMET P F ,PARMENTIER A B ,POELMAN D.Selecting conversion phosphors for white light-emitting diodes [J ].J.Electrochem.Soc .,2011,158(6):R37-R54.[3]KOMURO N ,MIKAMI M ,SHIMOMURA Y ,et al ..Synthesis ,structure and optical properties of cerium-doped calcium bari-um phosphate a novel blue-green phosphor for solid-state lighting [J ].J.Mater.Chem.C ,2015,3(1):204-210.[4]JANG H S ,IM W B ,LEE D C ,et al ..Enhancement of red spectral emission intensity of Y 3Al 4O 12ʒCe 3+phosphor via Pr co-doping and Tb substitution for the application to White LEDs [J ].J.Lumin .,2017,126(2):371-377.[5]TANNER P A.Some misconceptions concerning the electronic spectra of tri-positive europium and cerium [J ].Chem.Soc.Rev .,2013,42(12):5090-5101.[6]FUJITA S ,SAKAMOTO A ,TANABE S.Luminescence characteristics of YAG glass-ceramic phosphor for white LED [J ].IEEE J.Sel.Top.Quantum Electron .,2008,14(5):1387-1391.[7]ZHANG S A ,HU Y H.Photoluminescence spectroscopies and temperature-dependent luminescence of Mn 4+in BaGe 4O 9phosphor [J ].J.Lumin .,2016,177:394-401.[8]JIN Y H ,FU Y R ,HU Y H ,et al ..A high color purity deep red emitting phosphor SrGe 4O 9ʒMn 4+for warm white LEDs [J ].Powder Technol .,2016,292:74-79.[9]KIM M ,SINGH S P ,SHIM S ,et al ..Discovery of a quaternary sulfide ,Ba 2-x LiAlS 4ʒEu 2+,and its potential as a fast-deca-ying LED phosphor [J ].Chem.Mater .,2020,32(15):6697-6705.[10]LI C ,WANG X M ,CHI F F ,et al .A narrow-band blue emitting phosphor Ca 8Mg 7Si 9N 22ʒEu 2+for pc-LEDs [J ].J.Ma-ter.Chem.C ,2019,7(13):3730-3734.[11]JIA Y J ,PAN Y X ,ZHU J W ,et al ..In situ organic solvent-free synthesis of a novel red emitting Mn 4+doped KRbGeF 6phosphor at the room temperature [J ].Dalton Trans .,2020,49(38):13226-13232.[12]ZHOU Y ,WANG X M ,WANG C P ,et al ..A strong zero-phonon line red phosphor BaNbF 7ʒMn 4+for white LEDs [J ].Inorg.Chem.Front .,2020,7(18):3371-3378.[13]ELZER E ,STROBEL P ,WEILER V ,et al ..The highly efficient red-emitting phosphor Sr 2[BeAl 3N 4]ʒEu 2+[J ].Chem.Mater .,2020,32(15):6611-6617.[14]ZHU H M ,LIN C C ,LUO W Q ,et al ..Highly efficient non-rare-earth red emitting phosphor for warm white light-emitting diodes [J ].Natmmun .,2014,5(1):4312-1-10.[15]ZHOU Y ,ZHANG S ,WANG X M ,et al ..Structure and luminescence properties of Mn 4+-activated K 3TaO 2F 4red phosphorfor white LEDs [J ].Inorg.Chem .,2019,58(7):4412-4419.㊀第5期魏恒伟,等:Ba 2+调制SrGe 4-x O 9ʒx Mn 4+晶体结构及其发光性质649㊀[16]PENG M Y ,YIN X W ,TANNER P A ,et al ..Site occupancy preference ,enhancement mechanism ,and thermal resistance of Mn 4+red luminescence in Sr 4Al 14O 25ʒMn 4+for warm WLEDs [J ].Chem.Mater .,2015,27(8):2938-2945.[17]KONG L ,LIU Y Y ,DONG L P ,et al ..Enhanced red luminescence in CaAl 12O 19ʒMn 4+via doping Ga 3+for plant growthlighting [J ].Dalton Trans .,2020,49(6):1947-1954.[18]PARK W B.Color tuning of a Mn 4+doped phosphor :Sr 1-x Ba x Ge 4O 9ʒMn 4+0.005(0.00ɤx ɤ1.00)[J ].J.Korean Chem.Soc .,2017,61(4):163-167.[19]NISHI F.Strontium tetragermanate ,SrGe 4O 9[J ].Acta Cryst .,1996,C52:2393-2395.[20]XIA Z G ,LIU Q L.Progress in discovery and structural design of color conversion phosphors for LEDs [J ].Prog.Mater.Sci .,2016,84:59-117.[21]WANG B ,LIN H ,XU J ,et al ..CaMg 2Al 16O 27ʒMn 4+-based red phosphor :a potential color converter for high-powered warm W-LED [J ].ACS Appl.Mater.Interfaces ,2014,6(24):22905-22913.[22]LIANG S S ,SHANG M M ,LIAN H Z ,et al ..Deep red M Ge 4O 9ʒMn 4+(M =Sr ,Ba )phosphors :structure ,luminescence properties and application in warm white light emitting diodes [J ].J.Mater.Chem.C ,2016,4(26):6409-6416.[23]SHASHKOV A Y ,RANNEV N V ,VENEVTSEV Y N.Atomic structure of crystals of alpha-(PbGe 4O 9),BaGe 4O 9,and Pb 2/3Sr 1/3-Ge 4O 9and features of the coordination of germanium atoms in framework [J ].Sov.J.Coordinat.Chem .,1985,10(10):1420-1426.[24]QIU S J ,WEI H W ,WANG X M ,et al ..Red emitting phosphor K 2SiF 6ʒMn 4+:controlled synthesis ,growth mechanism ,and shape-dependent luminescence properties [J ].J.Lumin .,2020,226:117426.[25]WANG B ,LIN H ,HUANG F ,et al ..Non-rare-earth BaMgAl 10-2x O 17ʒx Mn 4+,x Mg 2+:a narrow-band red phosphor for use as a high-power warm W-LED [J ].Chem.Mater .,2016,28(10):3515-3524.[26]张延,刘升,许虹杰,等.LED 用荧光玻璃的制备及性能研究[J].无机材料学报,2015,30(6):588-592.ZHANG Y,LIU S,XU H J,et al ..Preparation and performance of CeʒYAG phosphor-in-glass [J].J.Inorg.Mater .,2015,30(6):588-592.(in Chinese)[27]WANG J,TSAI C C,CHENG W C,et al ..High thermal stability of phosphor-converted white light-emitting diodes emplo-ying CeʒYAG-doped glass [J].IEEE J.Sel.Top.Quantum Electron .,2011,17(3):741-746.[28]岳相铭,林航,林世盛,等.La 3Si 6N 11ʒCe 3+荧光玻璃陶瓷及其在高功率固态照明中的应用[J].发光学报,2020,41(12):1529-1537.YUE X M,LIN H,LIN S S,et al 3Si 6N 11ʒCe 3+luminescent glass ceramics applicable to high-power solid-state lighting [J].Chin .J.Lumin .,2020,41(12):1529-1537.(in Chinese)[29]朱学绘,范广涵,王海丽,等.新型CeʒYAG 陶瓷荧光体封装白光LED 的性能[J].功能材料与器件学报,2010,16(4):389-393.ZHU X H,FAN G H,WANG H L,et al ..White LED packaged by novel CeʒYAG ceramic phosphor [J].J.Funct.Ma-ter.Dev .,2010,16(4):389-393.(in Chinese)[30]黄海宇,向卫东,张志敏,等.YAGʒCe,Mn 微晶玻璃的制备及光谱性能研究[J].中国稀土学报,2012,30(6):726-731.HUANG H Y,XIANG W D,ZHANG Z M,et al ..Preparation and luminescence properties of cerium,manganese co-doping YAG glass ceramics [J].J.Chin.Rare Earth Soc .,2012,30(6):726-731.(inChinese)魏恒伟(1988-),男,陕西周至人,博士,实验师,2017年于陕西师范大学获得博士学位,主要从事白光LED 用无机发光材料的研究E-mail:whwsnnu@.cn焦桓(1968-),女,陕西三原人,博士,教授,2001年于西北工业大学获得博士学位,主要从事固体无机材料㊁照明㊁显示与新能源发光材料的基础与应用研究㊂E-mail:jiaohuan@.cn李雅婷(1999-),女,内蒙古鄂尔多斯人,在读本科生,主要从事白光LED 用荧光粉的研究㊂E-mail:1922501831@。

《材料科学基础》名词解释AOrowan mechanism （奥罗万机制）位错绕过第二相粒子，形成包围第二相粒子的位错环的机制。

Austenite(奥氏体)碳在γ-Fe中形成的间隙固溶体称为奥氏体。

B布拉菲点阵除考虑晶胞外形外，还考虑阵点位置所构成的点阵。

Half-coherent interface（半共格相界）两相邻晶体在相界面处的晶面间距相差较大，则在相界面上不可能做到完全一一对应，于是在界面上将产生一些位错，以降低界面弹性应变能。

这时两相原子部分保持匹配，这样的界面称为半共格界面。

Sheet texture（板织构）轧板时形成的组织的择优取向。

Peritectic reaction（包晶反应）固相和液相生成另一成分的固溶体的反应Peritectic segregation（包晶偏析）新生成的固相的芯部保留残余的原有固相，新相本身成分也不均匀。

Peritectic phase diagram（包晶相图）具有包晶反应的相图Peritectoid reaction（包析反应）由两个固相反应得到一个固相的过程为包析反应。

Cellular structure（胞状结构）成分过冷区很小时，固相突出部分局限在很小区域内，不生成侧向枝晶。

Intrinstic diffusion coefficient（本征扩散系数）依赖热缺陷进行的扩散的扩散系数。

Transformed ledeburite（变态莱氏体）渗碳体和奥氏体组成的莱氏体冷却至727℃时奥氏体发生共析反应转变为珠光体，此时称变态莱氏体。

Deformation twins（变形孪晶）晶体通过孪生方式发生塑性变形时产生的孪晶（BCC，HCP）Chill zone（表层细晶区）和低温铸模模壁接触，强烈过冷形成的细小的方向杂乱的等轴晶粒细晶区。

Burger’s vector（柏氏矢量）表征位错引起的晶格点阵畸变大小和方向的物理量。

Asymmetric tilt boundary（不对称倾斜晶界）晶界两侧晶粒不对称的小角度晶界，界面含两套垂直的刃型位错。

材料科学基础专业词汇:第一章晶体结构原子质量单位Atomic mass unit (amu) 原子数Atomic number原子量Atomic weight 波尔原子模型Bohr atomic model键能Bonding energy 库仑力Coulombic force共价键Covalent bond 分子的构型molecular configuration 电子构型electronic configuration 负电的Electronegative正电的Electropositive 基态Ground state氢键Hydrogen bond 离子键Ionic bond同位素Isotope 金属键Metallic bond摩尔Mole泡利不相容原理 Pauli exclusion principle 元素周期表Periodic table原子atom 分子molecule分子量molecule weight 极性分子Polar molecule量子数quantum number 价电子valence electron范德华键van der waals bond 电子轨道electron orbitals点群point group 对称要素symmetry elements各向异性anisotropy 原子堆积因数Atomic packing factor(APF)体心立方结构body-centered cubic (BCC) 面心立方结构face-centered cubic (FCC) 布拉格定律bragg’s law 配位数coordination number晶体结构crystal structure 晶系crystal system晶体的crystalline 衍射diffraction中子衍射neutron diffraction 电子衍射electron diffraction晶界grain boundary 六方密堆积hexagonal close-packed(HCP)鲍林规则Pauling’s rules NaCl型结构NaCl－type structure CsCl型结构Caesium Chloride structure 闪锌矿型结构Blende-type structure纤锌矿型结构Wurtzite structure 金红石型结构Rutile structure萤石型结构Fluorite structure 钙钛矿型结构Perovskite-type structure 尖晶石型结构Spinel-type structure 硅酸盐结构Structure of silicates岛状结构Island structure 链状结构Chain structure层状结构Layer structure 架状结构Framework structure滑石talc 叶蜡石pyrophyllite高岭石kaolinite 石英quartz长石feldspar 美橄榄石forsterite各向同性的isotropic 各向异性的anisotropy晶格lattice 晶格参数lattice parameters密勒指数miller indices 非结晶的noncrystalline多晶的polycrystalline 多晶形polymorphism单晶single crystal 晶胞unit cell电位electron states (化合)价valence电子electrons 共价键covalent bonding金属键metallic bonding 离子键Ionic bonding极性分子polar molecules 原子面密度atomic planar density衍射角diffraction angle 合金alloy粒度,晶粒大小grain size 显微结构microstructure显微照相photomicrograph 扫描电子显微镜scanning electronmicroscope (SEM)重量百分数weight percent 透射电子显微镜 transmission electronmicroscope (TEM)四方的tetragonal 单斜的monoclinic配位数coordination number材料科学基础专业词汇:第二章晶体结构缺陷缺陷defect, imperfection 点缺陷point defect线缺陷line defect, dislocation 面缺陷interface defect体缺陷volume defect 位错排列dislocation arrangement位错线dislocation line 刃位错edge dislocation螺位错screw dislocation 混合位错mixed dislocation晶界grain boundaries 大角度晶界high-angle grainboundaries 小角度晶界tilt boundary, 孪晶界twin boundaries位错阵列dislocation array 位错气团dislocation atmosphere位错轴dislocation axis 位错胞dislocation cell位错爬移dislocation climb 位错聚结dislocation coalescence位错滑移dislocation slip 位错核心能量dislocation core energy位错裂纹dislocation crack 位错阻尼dislocation damping位错密度dislocation density 原子错位substitution of a wrongatom间隙原子interstitial atom 晶格空位vacant lattice sites间隙位置interstitial sites 杂质impurities弗伦克尔缺陷Frenkel disorder 肖脱基缺陷Schottky disorder主晶相the host lattice 错位原子misplaced atoms缔合中心Associated Centers. 自由电子Free Electrons电子空穴Electron Holes 伯格斯矢量Burgers克罗各-明克符号K roger Vink notation 中性原子neutral atom材料科学基础专业词汇:第二章晶体结构缺陷-固溶体固溶体solid solution 固溶度solid solubility化合物compound 间隙固溶体interstitial solid solution置换固溶体substitutional solid solution 金属间化合物intermetallics不混溶固溶体immiscible solid solution 转熔型固溶体peritectic solid solution有序固溶体ordered solid solution 无序固溶体disordered solid solution 固溶强化solid solution strengthening 取代型固溶体Substitutional solidsolutions过饱和固溶体supersaturated solid solution 非化学计量化合物Nonstoichiometric compound材料科学基础专业词汇:第三章熔体结构熔体结构structure of melt 过冷液体supercooling melt玻璃态vitreous state 软化温度softening temperature粘度viscosity 表面张力Surface tension介稳态过渡相metastable phase 组织constitution淬火quenching 退火的softened玻璃分相phase separation in glasses 体积收缩volume shrinkage材料科学基础专业词汇:第四章固体的表面与界面表面surface 界面interface同相界面homophase boundary 异相界面heterophase boundary晶界grain boundary 表面能surface energy小角度晶界low angle grain boundary 大角度晶界high angle grain boundary 共格孪晶界coherent twin boundary 晶界迁移grain boundary migration 错配度mismatch 驰豫relaxation重构reconstuction 表面吸附surface adsorption表面能surface energy 倾转晶界titlt grain boundary扭转晶界twist grain boundary 倒易密度reciprocal density共格界面coherent boundary 半共格界面semi-coherent boundary 非共格界面noncoherent boundary 界面能interfacial free energy应变能strain energy 晶体学取向关系crystallographicorientation惯习面habit plane材料科学基础专业词汇:第五章相图相图phase diagrams 相phase组分component 组元compoonent相律Phase rule 投影图Projection drawing浓度三角形Concentration triangle 冷却曲线Cooling curve成分composition 自由度freedom相平衡phase equilibrium 化学势chemical potential热力学thermodynamics 相律phase rule吉布斯相律Gibbs phase rule 自由能free energy吉布斯自由能Gibbs free energy 吉布斯混合能Gibbs energy of mixing 吉布斯熵Gibbs entropy 吉布斯函数Gibbs function热力学函数thermodynamics function 热分析thermal analysis过冷supercooling 过冷度degree of supercooling杠杆定律lever rule 相界phase boundary相界线phase boundary line 相界交联phase boundarycrosslinking共轭线conjugate lines 相界有限交联phase boundarycrosslinking相界反应phase boundary reaction 相变phase change相组成phase composition 共格相phase-coherent金相相组织phase constentuent 相衬phase contrast相衬显微镜phase contrast microscope 相衬显微术phase contrastmicroscopy相分布phase distribution 相平衡常数phase equilibriumconstant相平衡图phase equilibrium diagram 相变滞后phase transition lag相分离phase segregation 相序phase order相稳定性phase stability 相态phase state相稳定区phase stabile range 相变温度phase transitiontemperature相变压力phase transition pressure 同质多晶转变polymorphictransformation同素异晶转变allotropic transformation 相平衡条件phase equilibriumconditions显微结构microstructures 低共熔体eutectoid不混溶性immiscibility材料科学基础专业词汇:第六章扩散活化能activation energy扩散通量diffusion flux浓度梯度concentration gradient菲克第一定律Fick’s first law菲克第二定律Fick’s second law相关因子correlation factor稳态扩散steady state diffusion非稳态扩散nonsteady-state diffusion 扩散系数diffusion coefficient跳动几率jump frequency填隙机制interstitalcy mechanism晶界扩散grain boundary diffusion 短路扩散short-circuit diffusion上坡扩散uphill diffusion下坡扩散Downhill diffusion互扩散系数Mutual diffusion渗碳剂carburizing浓度梯度concentration gradient 浓度分布曲线concentration profile扩散流量diffusion flux驱动力driving force间隙扩散interstitial diffusion自扩散self-diffusion表面扩散surface diffusion空位扩散vacancy diffusion扩散偶diffusion couple扩散方程diffusion equation扩散机理diffusion mechanism扩散特性diffusion property无规行走Random walk达肯方程Dark equation柯肯达尔效应Kirkendall equation本征热缺陷Intrinsic thermal defect本征扩散系数Intrinsic diffusion coefficient离子电导率Ion-conductivity空位机制Vacancy concentration材料科学基础专业词汇:第七章相变过冷supercooling 过冷度degree of supercooling 晶核nucleus 形核nucleation形核功nucleation energy 晶体长大crystal growth均匀形核homogeneous nucleation 非均匀形核heterogeneous nucleation形核率nucleation rate 长大速率growth rate 热力学函数thermodynamics function临界晶核critical nucleus 临界晶核半径critical nucleus radius枝晶偏析dendritic segregation 局部平衡localized equilibrium平衡分配系数equilibriumdistributioncoefficient有效分配系数effective distribution coefficient成分过冷constitutional supercooling 引领（领先）相leading phase共晶组织eutectic structure 层状共晶体lamellar eutectic伪共晶pseudoeutectic 离异共晶divorsed eutectic表面等轴晶区chill zone 柱状晶区columnar zone中心等轴晶区equiaxed crystal zone 定向凝固unidirectional solidification 急冷技术splatcooling 区域提纯zone refining单晶提拉法Czochralski method 晶界形核boundary nucleation位错形核dislocation nucleation 晶核长大nuclei growth斯宾那多分解spinodal decomposition有序无序转变disordered-order transition马氏体相变martensite phase transformation 马氏体martensite材料科学基础专业词汇:第八、九章固相反应和烧结固相反应solid state reaction 烧结sintering烧成fire 合金alloy再结晶Recrystallization 二次再结晶Secondary recrystallization 成核nucleation 结晶crystallization子晶，雏晶matted crystal 耔晶取向seed orientation异质核化heterogeneous nucleation 均匀化热处理homogenization heattreatment铁碳合金iron-carbon alloy 渗碳体cementite铁素体ferrite 奥氏体austenite共晶反应eutectic reaction 固溶处理solution heat treatment。

Crystal Structure and the Paraelectric-to-Ferroelectric PhaseTransition of Nanoscale BaTiO3Millicent B.Smith,†Katharine Page,‡Theo Siegrist,§Peter L.Redmond,†Erich C.Walter,†Ram Seshadri,‡Louis E.Brus,†and Michael L.Steigerwald*,†Department of Chemistry,Columbia Uni V ersity,3000Broadway,New York,New York10027,Materials Department and Materials Research Laboratory,Uni V ersity of California,Santa Barbara,California93106,and Bell Laboratories,600Mountain A V enue,Murray Hill,New Jersey07974Received August3,2007;E-mail:mls2064@Abstract:We have investigated the paraelectric-to-ferroelectric phase transition of various sizes ofnanocrystalline barium titanate(BaTiO3)by using temperature-dependent Raman spectroscopy and powderX-ray diffraction(XRD).Synchrotron X-ray scattering has been used to elucidate the room temperaturestructures of particles of different sizes by using both Rietveld refinement and pair distribution function(PDF)analysis.We observe the ferroelectric tetragonal phase even for the smallest particles at26nm.Byusing temperature-dependent Raman spectroscopy and XRD,wefind that the phase transition is diffusein temperature for the smaller particles,in contrast to the sharp transition that is found for the bulk sample.However,the actual transition temperature is almost unchanged.Rietveld and PDF analyses suggestincreased distortions with decreasing particle size,albeit in conjunction with a tendency to a cubic averagestructure.These results suggest that although structural distortions are robust to changes in particle size,what is affected is the coherency of the distortions,which is decreased in the smaller particles.IntroductionBarium titanate(BaTiO3)is a ferroelectric oxide that under-goes a transition from a ferroelectric tetragonal phase to aparaelectric cubic phase upon heating above130°C.In cubicperovskite BaTiO3,the structure of which is displayed in Figure1a,titanium atoms are octahedrally coordinated by six oxygenatoms.Ferroelectricity in tetragonal BaTiO3is due to an averagerelative displacement along the c-axis of titanium from itscentrosymmetric position in the unit cell and consequently thecreation of a permanent electric dipole.The tetragonal unit cellis shown in Figure1b.The elongation of the unit cell along thec-axis and consequently the deviation of the c/a ratio from unityare used as an indication of the presence of the ferroelectricphase.1–3Ferroelectric properties and a high dielectric constant make BaTiO3useful in an array of applications such as multilayer ceramic capacitors,4,5gate dielectrics,6waveguide modulators,7,8IR detectors,9and holographic memory.10The dielectric and ferroelectric properties of BaTiO3are known to correlate with size,and the technological trend toward decreasing dimensions makes it of interest to examine this correlation when sizes are at the nanoscale.11–16†Columbia University.‡University of California.§Bell Laboratories.(1)Jaffe,B.;Cook,W.R.;Jaffe,H.Piezoelectric Ceramics,Vol.3;Academic Press:New York,1971.(2)Lines,M.E.;Glass,A.M.Principles and Applications of Ferroelec-trics and Related Materials;Clarendon Press:Oxford,1977.(3)Strukov,B.A.;Levanyuk,A.P.Ferroelectric Phenomena in Crystals;Springer-Verlag:Berlin,1998.(4)Wang,S.F.;Dayton,G.O.J.Am.Ceram.Soc.1999,82,2677–2682.(5)Hennings,D.;Klee,M.;Waser,R.Ad V.Mater.1991,3,334–340.(6)Yildirim,F.A.;Ucurum,C.;Schliewe,R.R.;Bauhofer,W.;Meixner,R.M.;Goebel,H.;Krautschneider,W.Appl.Phys.Lett.2007,90, 083501/1–083501/3.(7)Tang,P.;Towner,D.J.;Meier,A.L.;Wessels,B.W.IEEE PhotonicTech.Lett.2004,16,1837–1839.(8)Petraru,A.;Schubert,J.;Schmid,M.;Buchal,C.Appl.Phys.Lett.2002,81,1375–1377.(9)Pevtsov,E.P.;Elkin,E.G.;Pospelova,M.A.Proc.SPIE-Int.Soc.Opt.Am.,1997,3200,179-182.(10)Funakoshi,H.;Okamoto,A.;Sato,K.J.Mod.Opt.2005,52,1511–1527.(11)Shaw,T.M.;Trolier-McKinstry,S.;McIntyre,P.C.Annu.Re V.Mater.Sci.2000,30,263–298.(12)Frey,M.H.;Payne,D.A.Phys.Re V.B1996,54,3158–3168.(13)Zhao,Z.;Buscaglia,V.;Vivani,M.;Buscaglia,M.T.;Mitoseriu,L.;Testino,A.;Nygren,M.;Johnsson,M.;Nanni,P.Phys.Re V.B2004, 70,024107.(14)Buscaglia,V.;Buscaglia,M.T.;Vivani,M.;Mitoseriu,L.;Nanni,P.;Terfiletti,V.;Piaggio,P.;Gregora,I.;Ostapchuk,T.;Pokorny,J.;Petzelt,J.J.Eur.Ceram.Soc.2006,26,2889–2898.Figure1.Unit cell of BaTiO3in both the(a)cubic Pm-3m structure and (b)tetragonal P4mm structure.In the tetragonal unit cell,atoms are displaced in the z-direction,and the cell is elongated along the c-axis.Atom positions: Ba at(0,0,0);Ti at(1/2,1/2,z);O1at(1/2,1/2,z);and O2at(1/2,0,z). Displacements have been exaggerated forclarity.Published on Web05/08/200810.1021/ja0758436CCC:$40.75 2008American Chemical Society J.AM.CHEM.SOC.2008,130,6955–696396955Many experimental and theoretical17–25studies have indicated that the phase-transition temperature of BaTiO3is size-depend-ent,with the ferroelectric phase becoming unstable at room temperature when particle diameter decreases below a critical size.However,both theoretical and experimental reports of this critical size encompass a broad range of sizes.The experimental discrepancies may arise because of intrinsic differences between ferroelectric samples,because the transition is sensitive to conditions such as compositional variation,26lattice defects,12 strain,27or surface charges.20Furthermore,the differences in cell parameters between the two phases are small compared to other sources of broadening in diffraction data,likely leading to an overestimation of the critical size.Recent work by Fong et al.on perovskite(PbTiO3)thinfilms indicates that ferroelec-tric behavior persists down to a thickness of only three unit cells,25a value significantly less than that suggested by previous experimental studies.Several theoretical studies have been particularly useful in furthering the understanding of the observed behavior of ferroelectrics at small sizes.17However,ferroelectrics are particularly sensitive to surface effects,making modeling increasingly complicated as dimensions are reduced.Many models based on Landau theory18overestimate critical sizes;it has been suggested that this overestimation has resulted from the use of material parameters in the free-energy expression that were derived from the bulk material.19Spanier et al.have found by theoretical modeling that certain surface termination of thin films can stabilize polarization down to a thickness of only several unit cells.20Their calculations,which take into account experimentally determined nanoscale material parameters,es-timate the critical size for a BaTiO3sphere to be4.2nm.Other theoretical treatments,such as effective Hamiltonian and ab initio calculations,have predicted the presence of ferroelectricity in perovskitefilms as thin as three unit cells.23,24Various experimental probes of the structure of BaTiO3have revealed a complex and sometimes controversial picture.In the study of bulk material,structural transformations have been explained by averaging domains that are locally rhombo-hedral.28,29For the tetragonal phase,the titanium atoms are distorted in the〈111〉directions and oriented with a net displacement in the c-direction.A number of studies have reported evidence of disorder within BaTiO3above the transition temperature,supporting the existence of distortions within the cubic phase.30–32X-ray diffraction(XRD)studies produce data that are consistent with an increasingly cubic structure at smaller particle sizes,not distinguishing between average and local structure.12,33In contrast,Raman results have supported the existence of tetragonal symmetry at small dimensions,even though it was not discernible by XRD.34The disagreement between Raman and diffraction studies suggests that the phase transition in bulk BaTiO3is complex,with order-disorder as well as displacive character.12,35,36Extended X-ray absorptionfine structure(EXAFS)and X-ray absorption near-edge structure(XANES)studies of bulk BaTiO3 have supported a dominant order-disorder component to the structural phase transitions.29In EXAFS and XANES analysis of10,35,and70nm BaTiO3particles,37Frenkel et al.find titanium displacements for all samples studied,in contrast to their cubic macroscopic crystal structures from laboratory XRD. Petkov et al.38have recently demonstrated the use of the pair distribution function(PDF)to understand local structure distor-tions and polar behavior in Ba x Sr1-x TiO3(x)1,0.5,0) nanocrystals.They found that locally,refining over thefirst15Å,the tetragonal model was the bestfit to the experimental PDF;however,over longer distances(15-28Å),the cubic model was the bestfit.Their conclusion was that5nm BaTiO3 is on average cubic,but that tetragonal-type distortions in the Ti-O distances are present within the cubic structure.They did not,however,find the distortions to be inherent to small particles because they were not present in the perovskite SrTiO3. Several preparation strategies have been reported in recent years for high-quality,well-defined BaTiO3nanocrystalline samples.Hydrothermal or solvothermal methods have been systematically used to make nanocrystalline BaTiO3.39–42O’Brien et al.43and Urban et al.21,44have produced BaTiO3particles and rods,respectively,from the reaction of a bimetallic alkoxide precursor with hydrogen peroxide.Niederberger et al.report a solvothermal preparation of5nm particles of BaTiO3and(15)Hoshina,T.;Kakemoto,H.;Tsurumi,T.;Wada,S.;Yashima,M.J.Appl.Phys.2006,99,054311–054318.(16)Yashima,M.;Hoshina,T.;Ishimura,D.;Kobayashi,S.;Nakamura,W.;Tsurumi,T.;Wada,S.J.Appl.Phys.2005,98,014313. (17)Duan,W.;Liu,Z.-R.Curr.Opin.Solid State Mater.Sci.2006,10,40–51.(18)Wang,C.L.;Smith,S.R.P.J.Phys.:Condens.Matter1995,7163–7171.(19)Akdogan,E.K.;Safari,A.J.Appl.Phys.2007,101,064114.(20)Spanier,J.E.;Kolpak,A.M.;Urban,J.J.;Grinberg,I.;Ouyang,L.;Yun,W.S.;Rappe,A.M.;Park,H.Nano Lett.2006,6,735–739.(21)Urban,J.J.;Spanier,J.E.;Lian,O.Y.;Yun,W.S.;Park,H.Ad V.Mater.2003,15,423–426.(22)Urban,J.J.Synthesis and Characterization of Transition Metal Oxideand Chalcogenide Nanostructures.Ph.D.Dissertation,Harvard Uni-versity,Cambridge,MA,2004.(23)Ghosez,P.;Rabe,K.M.Appl.Phys.Lett.2000,76,2767–2769.(24)Meyer,B.;Vanderbilt,D.Phys.Re V.B2001,63,205426.(25)Fong,D.D.;Stephenson,G.B.;Streiffer,S.K.;Eastman,J.A.;Auciello,O.;Fuoss,P.H.;Thompson,C.Science2004,304,1650–1653.(26)Lee,S.;Liu,Z.-K.;Randall,C.A.J.Appl.Phys.2007,101,054119.(27)Choi,K.J.;Biegalski,M.;Li,Y.L.;Sharan,A.;Schubert,J.;Uecker,R.;Reiche,P.;Chen,Y.B.;Pan,X.Q.;Gopalan,V.;Chen,L.-Q.;Schlom,D.G.;Eom,C.B.Science2004,306,1005–1009. (28)Kwei,G.H.;Lawson,A.C.;Billinge,S.J.L.;Chong,S.-W.J.Phys.Chem.1993,97,2368–2377.(29)Ravel,B.;Stern,E.A.;Vedrinskii,R.I.;Kraizman,V.Ferroelectrics1998,206–207,407–430.(30)Zalar,B.;Laguta Valentin,V.;Blinc,R.Phys.Re V.Lett.2003,90,037601.(31)Lambert,M.;Comes,R.Solid State Commun.1968,6,715–719.(32)Comes,R.;Lambert,M.;Guinier,A.Acta Crystallogr.,Sect.A:Cryst.Phys.,Diffr.,Theor.Gen.Crystallogr.1970,26,244–254.(33)Wada,S.;Tsurumi,T.;Chikamori,H.;Noma,T.;Suzuki,T.J.Cryst.Growth2001,229,433–439.(34)El Marssi,M.;Le Marrec,F.;Lukyanchuk,I.A.;Karkut,M.G.J.Appl.Phys.2003,94,3307–3312.(35)Wada,S.;Suzuki,T.;Osada,M.;Kakihana,M.;Noma,T.Jpn.J.Appl.Phys.1998,37,5385–5393.(36)Noma,T.;Wada,S.;Yano,M.;Suzuki,T.Jpn.J.Appl.Phys.1996,80,5223–5233.(37)Frenkel,A.I.;Frey,M.H.;Payne,D.A.J.Synchrotron Radiat.1999,6,515–517.(38)Petkov,V.;Gateshki,M.;Niederberger,M.;Ren,Y.Chem.Mater.2006,18,814–821.(39)Jung,Y.-J.;Lim,D.-Y.;Nho,J.-S.;Cho,S.-B.;Riman,R.E.;Lee,B.W.J.Cryst.Growth2005,274,638–652.(40)Yosenick,T.;Miller,D.;Kumar,R.;Nelson,J.;Randall,C.;Adair,J.J.Mater.Res.2005,20,837–843.(41)Guangneng,F.;Lixia,H.;Xueguang,H.J.Cryst.Growth2005,279,489–493.(42)Joshi,U.A.;Yoon,S.;Baik,S.;Lee,J.S.J.Phys.Chem.B2006,110,12249–12256.(43)O’Brien,S.;Brus,L.;Murray,C.B.J.Am.Chem.Soc.2001,123,12085–12086.(44)Urban,J.J.;Yun,W.S.;Gu,Q.;Park,H.J.Am.Chem.Soc.2002,124,1186–1187.6956J.AM.CHEM.SOC.9VOL.130,NO.22,2008A R T I C L E S Smith et al.SrTiO3from titanium isopropoxide and metallic barium or strontium in benzyl alcohol.45Here,we describe the use of a bimetallic alkoxide precursor in conjunction with solvothermal techniques to produce high-quality nanoparticles of BaTiO3with controllable sizes.We have studied particles with average sizes of26,45,and70nm by temperature-dependent Raman spectroscopy and XRD and with room temperature Rietveld and atomic PDF analysis of high-energy,high momentum-transfer synchrotron X-ray diffraction data.The sample particles are unstrained,because they are not thin-film samples and are compositionally homogeneous with, in particular,no discernible OH impurities that are known to plague many low-temperature solution preparations of ferro-electric oxides.12,33,36The complementary structural methods we employ provide information on different time and length scales.Raman spectra reflect the local symmetry around the scattering sites and are averaged over different parts of the sample.The X-ray techniques both allow an average depiction of the structure (through pattern matching and Rietveld analysis)and provide information on the near-neighbor length scale through PDF. The outcomes of the current study are consistent between the different techniques and are somewhat surprising.Raman spectroscopy indicates that the small particles undergo a more diffuse phase transition than in the bulk,although the T C remains nearly unchanged.Careful temperature-dependent XRD studies show that all sizes of particles are tetragonal until close to the bulk T C,and yet the smaller particles seem more cubic by using the c/a ratio as the metric.Average(Rietveld)and local(PDF) structure analyses of X-ray synchrotron data show that as the particle size is reduced,there is a clear and surprising trend toward increasing structural distortion.The increase in the off-centering of the titanium cation as particle size decreases in conjunction with the decrease in the c/a ratios is consistent with diminished structural coherence in smaller particles. Experimental SectionPreparation of BaTiO3Nanoparticles.Anhydrous benzene, isopropanol,dendritic barium(99.99%),and titanium isopropoxide (99.999%)were obtained from Aldrich Chemical Co.and used as received.Sintered pieces of BaTiO3were also purchased from Aldrich for use as a bulk standard.The bimetallic precursor BaTi[OC3H7]6was prepared according to Urban et al.44Parr acid digestion bombs with23mL Teflon liners were used for the solvothermal reaction.In a typical synthesis,10mmol(5.4g)of the precursor,BaTi[OC3H7]6,was added to the Teflon liner of a digestion bomb under an inert atmosphere.A total of10mL of solvent was added to the precursor underflowing argon according to the water and isopropanol ratios in Table1.In none of the solvents used did the precursor dissolve,but rather it formed a thick white suspension.The Teflon liner was tightly sealed inside the acid digestion bomb,and the mixture was heated in an oven at 220°C for18h.The resulting white precipitate was collected by centrifugation,washed with ethanol,and allowed to dry underambient conditions.A white powder suitable for powder XRD andRaman measurements was produced with a typical yield of1.93g.Transmission electron microscope(TEM)images were taken on aJEOL100CX instrument by using an accelerating voltage of100kV.Raman Spectroscopy.Raman spectroscopy was performed in air by using a backscattering micro-Raman spectrometer withhelium-neon laser(633nm)excitation.A home-built thermoelec-tric heating stage was used for temperature-dependent measure-ments.Spectra were taken at temperatures ranging from roomtemperature to above150°C.The300cm-1peak35wasfit to aLorentzian line shape on a sloping baseline,and from thisfit,thescaled peak area and linewidth were determined.Differential Scanning Calorimetry.Differential scanning cal-orimetry(DSC)was performed on a Perkin-Elmer Pyris1DSC.For each scan,3-4mg of sample was used.The heating profileconsisted of two cycles of heating from0to150°C at a rate of10°C/min and then cooling from150to0°C at that same rate. Thermodiffraction.X-ray diffraction data were obtained by using a Rigaku rotating anode together with a custom-built four-circle diffractometer.Graphite monochromated Cu K radiation(1.39217Å),together with a matched graphite analyzer,was usedin Bragg-Brentano geometry.In this way,a well-defined powderdiffraction profile was obtained for all reflections,allowing adetailed analysis of the profile changes associated with theparaelectric-to-ferroelectric phase transition.The intensities werenormalized to the incident beam to eliminate drift over the dataacquisition time.A home-built heating stage was used to reachtemperatures up to150°C.X-ray patterns above143°C werecollected to obtain a cubic reference for the expected increase inthe peak widths with2θ.Full pattern refinements were executedin the program Winprep46by using the profile parameters obtainedfrom the cubic phase above143°C.Synchrotron X-ray Diffraction.Synchrotron powder diffrac-tion data were collected in transmission mode at beamline11-ID-B of the Advanced Photon Source,Argonne National Laboratory,by utilizing high-energy X-rays(∼90kV)at room temperature.The use of high-energy X-rays enables measure-ments at longer wavevectors,Q)4πsin(θ/λ),which is important for the application of the PDF technique.Samples were loaded in Kapton tubes,and scattering data were collected on an image plate system(amorphous silicon detector from General Electric Healthcare)with sample-to-detector distances of660 mm for Rietveld refinement data and150mm for PDF data. The raw data sets were processed to one-dimensional X-ray diffraction data by using the program FIT2D.47A bulk internal standard was used to calibrate the processed data,to supply an effective wavelength ofλ)0.13648Åfor refinements.Rietveld refinement of the synchrotron data was carried out in the XND program.48Lattice parameters,atomic positions,and atomic displacement parameters were refined.The PDF,G(r))4πr[F(r)-F],was extracted from the processed scattering data asdescribed by Chupas et al.49with a maximum momentum transferof Q)24Å-1by using the program PDFGETX2.50In thisequation,F(r)is the local atomic number density,F0is theaverage atomic number density,and r is the radial distance.Fullstructure profile refinements were carried out in the programsPDFfit2and PDFgui.51The scale factor,lattice parameters,(45)Niederberger,M.;Garnweitner,G.;Pinna,N.;Antonietti,M.J.Am.Chem.Soc.2004,126,9120–9126.(46)Stahl,K.Winprep;Lyngby,Denmark.(47)Hammersley,A.P.;Svensson,S.O.;Hanfland,M.;Fitch,A.N.;Hausermann,D.High Pressure Res.1996,14,235–248.(48)Bèrar,J.F.;Garnier,P.NIST Spec.Publ.1992,846,212.(49)Chupas,P.J.;Qui,X.;Hanson,J.C.;Lee,P.L.;Grey,C.P.;Billinge,S.J.L.J.Appl.Crystallogr.2003,36,1342–1347.(50)Qiu,Y.;Wu,C.Q.;Nasu,K.Phys.Re V.B2005,72,224105-1–224105-7.(51)Farrow,C.L.;Thompson,J.W.;Billinge,S.J.L.J.Appl.Crystallogr.2004,37,678.Table1.Particle Size Dependence on Solvent Compositionwater:isopropanol(v:v)particle size(nm)1:070(1040:6060(1030:7045(920:8026(50:1∼10J.AM.CHEM.SOC.9VOL.130,NO.22,20086957 Paraelectric-to-Ferroelectric Phase Transition of Nanoscale BaTiO3A R T I C L E Satomic displacement parameters,and atomic positions as well as broadening from the sample and the instrument resolution were refined.Results and DiscussionPreparation of BaTiO 3Nanoparticles.We explored the effectsof reaction conditions such as temperature,precursor concentra-tion,solvent composition,and addition of surfactants in the preparation of BaTiO 3nanoparticles.We found that the composition of the solvent played a critical role in determining the size of the particles,pure water producing the largest sizes and pure isopropanol producing the smallest.A TEM was used to determine the particle size and morphology,and typical images are shown in Figure 2,with histograms of the particle-size distributions displayed as insets.The particles were nearly spherical in shape with average sizes of 70,45,and 26nm.Table 1gives the average particle size obtained with each solvent mixture as determined by TEM;the given error is plusor minus one standard deviation.Scherrer analysis 52of the laboratory XRD (111)peak at room temperature gave X-ray coherence lengths (grain sizes)of 33,29,and 21nm for the 70,45and 26nm particles,respectively.The instrumental line width limits the determination of particle size to a maximum of 35nm,preventing any conclusions about the single crystal-linity (grain size)of the 70nm particles.However,for the two smaller sizes,the individual particles are likely single crystals.The final size of the particles is determined by the balance between particle nucleation and growth.In order to form BaTiO 3from the alkoxide precursor,M -O -M bonds must be formed from M -OR species (M )Ti,Ba;R )-OC 3H 7).In the mixed solvent system,it is likely that several mechanisms are in competition with one another,determining the reaction pathway.In pure water,the pH of the solvent -precursor solution was 13,suggesting the partial hydrolysis of the precursor to Ba(OH)2.This M -OH species can react with a second M -OH or with an M -OR to form the M -O -M bonds and water or isopro-panol,respectively.M -O -M bonds might also form through a -hydride elimination and the reaction of the metal hydride with an M -OR.An additional effect of the solvent composition is that the isopropyl group is a better capping group than the hydroxide because -OC 3H 7is less reactive than -OH.Isopro-poxy moieties on the surface of a particle passivate the surface,inhibiting particle growth and leading to smaller particle sizes.Raman Spectroscopy.Tetragonal BaTiO 3has 10Raman-active modes.When splitting of transverse and longitudinal optical modes,as well as splitting due to differing polarizability in each unit cell direction is considered,18Raman-active phonons result.53Symmetry demands that cubic BaTiO 3should be completely Raman-inactive.However,broad peaks centered at 260and 530cm -1are still observed above the cubic-to-tetragonal phase-transition temperature.34The Raman activity of the cubic phase has been generally attributed in the literature to disorder of titanium in the nominally cubic phase.53Figure 3shows the Raman spectrum of (a)bulk,(b)70nm,(c)45nm,and (d)26nm BaTiO 3over a range of temperatures between 25and 150°C.The assignments given to the Raman modes at the top of Figure 3are those reported in the literature.34Below 200cm -1,we find some weak scattering in the nanoparticle samples due to a BaCO 3impurity.As seen by others,the BaTiO 3Raman spectra have the broad features characteristic of titanium disorder in the unit cell at all temperatures and at all sizes.In the bulk BaTiO 3spectra in Figure 3a,the intensities of the E (LO +TO),B 1peaks at ∼300cm -1and E (LO),A 1(LO)peaks at ∼715cm -1decrease rapidly as the temperature increases through the bulk T C ,an observation consistent with prior reports.35We interpret the disappearance of the 300cm -1peak as an indicator of the tetragonal phase and use two characteristics as an indication of the phase transition.The first is an increase in peak width at the phase-transition temperature similar to that reported by Hoshina et al.,15and the second is the loss of peak intensity with increasing temperature.These values are given in Figure 4a -d.For all samples,the linewidth for the E (LO +TO),B 1peak increases both with increasing temperature and with decreasing particle size.The much larger linewidths of the Raman peaks of the nanoparticles suggest that the tetragonality present is accompanied by a significantly decreased structural coherence.(52)Cullity,B.D.;Stock,S.R.Elements of X-ray Diffraction ,3rd ed.;Prentice Hall:Upper Saddle River,NJ,2001.(53)DiDomenico,M.;Wemple,S.H.;Porto,S.P.S.Phys.Re V .1968,174,522–530.Figure 2.TEM images of BaTiO 3nanoparticles.Histograms of individualparticle sizes,shown as insets,correspond to (a)70(10nm,(b)45(9nm,and (c)26(5nm.The 200nm scale bar is common to all three micrographs.6958J.AM.CHEM.SOC.9VOL.130,NO.22,2008A R T I C L E S Smith et al.It is interesting to note that bulk BaTiO 3near the cubic-to-tetragonal phase transition displays a Raman linewidth that is similar to the line width displayed by the 26nm particles at all temperatures.The linewidth analysis is complemented by the analysis of scaled peak area.Figure 4shows that near the expected phase-transition temperature of 130°C,there is a sharp drop in the Raman intensity of the 300cm -1peak for the bulk sample but a more gradual decrease in intensity over the entire temperature range for the 70and 45nm particles.In contrast,the peak area of the 26nm particles in Figure 4d is nearly constant over the entire temperature range.These results indicate a phase transition that becomes increasingly diffuse in temperature as the particle size decreases.The lack of a sharply defined phase transition in nanosized samples is also observed by using DSC.For bulk BaTiO 3,the DSC trace exhibits a peak near 130°C,indicative of the phase transition.Similar features are not observed in the DSC of nanoparticle samples.Together with the Raman results,these findings support the idea that the phase transition is distributed over a wide range of temperatures in the nanoparticles,although it is sharply defined in the bulk material.Thermodiffraction.The splitting of the X-ray diffraction peaks is well defined in terms of symmetry,allowing analysis of systematic changes for different (hkl )indices.Figure 5shows diffraction data for 70nm BaTiO 3at room temperature and at 148°C over a small 2θrange.In the high-symmetry cubic phase,no reflections are split.In the tetragonal phase,(222)remains a single peak whereas the (400)reflection is divided into (400/040)and (004)peaks with an intensity ratio of 2:1.Because the c /a ratio is larger than 1,the (004)reflection shifts to a lower 2θvalue,and the (400/040)reflection correspondingly shifts to a higher 2θvalue.In spite of changes in symmetry,the cubic-to-tetragonal phase transition is usually not well resolved in diffraction studies of nanosized BaTiO 3because of inherent line broadening due to small particle size.In our study,the phase evolution of BaTiO 3particles was determined by pattern matching to the laboratory X-raydif-Figure 3.Raman spectra at different temperatures for (a)bulk BaTiO 3,(b)70nm particles,(c)45nm particles,and (d)26nm particles.Temperatures increase from top to bottom in each panel.Temperatures are specified to be within a range of up to (3°C.The locations of Raman modes are indicated at the top of the figure.The features below 200cm -1are due to a trace BaCO 3impurity,and these are not found in the bulksample.Figure 4.Results from fits to the Raman data.Filled circles show variationof the linewidth of the 300cm -1Raman signal as a function of temperature.Open squares are intensities of the 300cm -1Raman signal normalized to the intensity at 280cm -1.Displayed for (a)bulk powder,(b)70nm particles,(c)45nm particles,and (d)26nmparticles.Figure 5.70nm BaTiO 3particle laboratory XRD data shown over a small 2θrange.(a)Recorded at room temperature.(b)Recorded at 148°C.Reflections have been labeled for the cubic phase in panel b.The (222)peak does not split in the tetragonal phase,and consequently,the peak width is constant with temperature.Peaks which are degenerate in the cubic phase but not in the tetragonal phase,for example cubic (400),widen and lose intensity upon cooling.J.AM.CHEM.SOC.9VOL.130,NO.22,20086959Paraelectric-to-Ferroelectric Phase Transition of Nanoscale BaTiO 3A R T I C L E S。

材料科学基础英文版Material Science Fundamentals。

Material science is an interdisciplinary field that explores the properties of materials and their applications in various industries. It combines elements of physics, chemistry, engineering, and biology to understand the behavior of materials at the atomic and molecular levels. This English version of the material science fundamentals aims to provide a comprehensive overview of the key concepts and principles in this field.1. Introduction to Material Science。

Material science is concerned with the study of materials and their properties. It encompasses the discovery, design, and development of new materials, as well as the investigation of existing materials for specific applications. The field is essential for the advancement of technology and innovation in various industries, including aerospace, automotive, electronics, and healthcare.2. Atomic Structure and Bonding。

材料科学专业英语词汇1. Material science - 材料科学2. Properties - 物性3. Structure - 结构5. Mechanical properties - 机械性能6. Thermal properties - 热性能7. Electrical properties - 电性能8. Optical properties - 光学性能9. Chemical properties - 化学性能10. Processing - 加工11. Synthesis - 合成12. Manufacturing - 制造13. Testing - 测试14. Characterization - 表征15. Nanomaterials - 纳米材料16. Polymers - 高分子材料17. Metals - 金属18. Ceramics - 陶瓷20. Biomaterials - 生物材料21. Material selection - 材料选择22. Material degradation - 材料退化23. Corrosion - 腐蚀24. Fracture - 断裂25. Fatigue - 疲劳26. Deformation - 变形27. Microstructure - 微观结构28. Phase transformation - 相变29. Crystal structure - 晶体结构30. Surface engineering - 表面工程31. Coating - 涂层32. Thin films - 薄膜33. Materials characterization techniques - 材料表征技术34. X-ray diffraction - X射线衍射35. Scanning electron microscopy - 扫描电子显微镜36. Transmission electron microscopy - 透射电子显微镜37. Atomic force microscopy - 原子力显微镜38. Differential scanning calorimetry - 差示扫描量热计39. Tensile testing - 拉伸试验。

专业英语词汇索引By材控1004 （一）castingcasting 铸造，铸件pour 浇注refractory 难熔化的mould 铸型cavity 空腔founding 铸造core 芯子lost wax 失蜡（铸造）crucible steel 坩埚钢ferrous 含铁的，即黑色的（金属）non- ferrous 不含铁的，即有色的（金属）forging 锻造dimensional accuracy 尺寸精度surface finish 表面光洁度die casting 压力铸造sand casting 砂型铸造defects 缺陷pattern 模型parting line 分型线flask 砂箱cope 上箱drag 下箱spruce 直浇道runner 横浇道gate 内浇道riser 冒口moulding platform 造型台clearance 吃砂量facing sand 面砂moulding sand 型砂vent hole 通气孔aligning校正baking 焙烧inclusion 夹杂物（二）Foundations of Materials Sciencesolidification 凝固ceramics 陶瓷freezing temperature 结晶温度nucleation 形核short-range order 短程有序crystal structure 晶体结构embryo 晶坯undercooled 过冷（状态）nucleus 晶核spontaneously 自发的homogeneous nucleation均质形核critical nucleus 临界晶核latent heat of fusion 熔化潜热heterogeneous nucleation非均质形核grain refinement 晶粒细化剂inoculation 孕育处理boron 硼titanium boride 钛的硼化物grain boundary 晶界specific heat 比热radiation （热）辐射conduction （热）传导dendrite arm 枝晶臂precipitate 沉淀（相）或析出(相)lattice defect 晶体缺陷lead-tin alloy 铅锡合金solubility 溶解度solvus temperature 固相线温度matrix structure 基体grain 晶粒cooling rate 冷却速度solvus line 固相线dislocation 位错solvent 溶剂solute 溶质yield strength 屈服强度tensile strength 抗拉强度microconstituent 显微组织crack 裂纹segregation 偏析eutectic 共晶quench 淬火（三）Cast alloysferrous 含铁的（黑色）金属steel furnace 炼钢炉resistance to shock 抗冲击plain carbon steel 普碳钢cast iron 铸铁screw 螺丝bolt 螺栓washer 垫圈shaft 轴hot working 热加工ferrite 铁素体austenite 奥氏体cementite 渗碳体pearlite 珠光体shrinkage 收缩brass 黄铜bronze 青铜galvanizing 镀锌die casting 压力铸造(四）Forgingforge 锻造press 压力机impact blow 冲击作用forging press 锻压机open-die forging 开式模锻，自由锻closed-die forging 闭式模锻upset 镦粗free surface 自由表面extrusion 挤压piercing 穿孔，冲孔punching 冲孔blocking die 预锻模，粗压模finishing die 精锻模，成型模，终锻模blocking cavity 预锻模膛finishing cavity 终锻模膛ribbon 带flash 毛边rib 肋，加强部stroke 行程，冲程hydraulic press 液压机load capacity 载荷量，负荷容量stiffness 刚度power hammer 电锤，动力锤，机动锤potential energy 势能elongation 伸长，延伸substituting 带入bite 送进量，吃刀量，切入量spread ratio 宽展率，宽展系数deformation resistance 变形阻力die cavity 模腔electrode 电极forge shop 锻造车间parting line 分型线technical literature 专业文献etch 腐蚀hot shortness 热脆性stress relieving 应力消除cold shut 冷结discontinuity 间隔（不连续）chilling 制冷loose scale 疏松氧化铁皮underfill 未充满descale 除鳞tensile stress 拉应力internal crack 内部裂纹inclusion 夹杂物fiber structure 显微组织fatigue property 疲劳特性thermal residual stress 热残余应力（五）Sheet-Metal formingshearing 剪切，切变deep drawing 深冲sheet forming 板料成形tensile force 张力，拉力compressive force 压力，挤压力，压缩力fold 折叠wrinkle 起皱failure 断裂stretching 伸延，张延slide 滑块punch 冲头clamping pressure 合模压力，夹紧压力air cylinder 汽缸blanking 落料，冲裁zinc-base alloy 锌基合金curvature 曲率，弧度hydraulic cylinder 液压缸spinning 旋压brittle material 脆性材料ductile material 塑性材料fracture surface 断裂面product 乘积shearing strength 抗剪强度notching 切口，下凹trimming 修边，剪切periphery 周边，边界cam 凸轮elastic limit 弹性极限exponent 指数stress gradient 应力梯度power-law 幂律（六）Extrusioncontainer 挤压筒nickel-based alloy 镍基合金die holder 模座，模架，凹模固定板direct extrusion 正挤压，直接挤压electrical cable 电缆tin 锡headroom 净空，头上空间concentricity 同轴度，同心度refractory metal 耐高温金属thermal shock 热冲击oxidation 氧化作用liner 衬圈prestress 预压力homogeneity 均匀性carbon block炭精块，大块炭砖warpage 翘曲intrusion 侵入，干涉breakthrough 临界，穿透extrusion ratio 挤压比mass flow rate 质量流率，质量流速melting point 熔点heat-treatment 热处理trial and error 累试法，反复试验法bore 腔mild steel 低碳钢，软钢precoat 预涂polymeter 聚合物，聚合体magnesium alloy 镁合金atmospheric contamination 空气污染（七）Classification of WeldingProcessesmechanical 机械粘附法thermochemical 热化学反应法arc plasmas 电弧等离子加热法arc circuit 电弧电路electric arc 电弧radiant energy 辐射能laser welding 激光焊接electron beam welding 电子束焊接spot welding 点焊torch 焊枪（八）Methods of Weldingrecrystallization 再结晶resistance heating 电阻加热induction heating 感应加热friction welding 摩擦焊slag 熔渣weld bead 焊接熔滴slag inclusions 焊接中的夹渣flat position 平焊位置fluoride 氟化物gaseous shielding medium 气体保护介质electric arc 电弧hydrocarbons 碳氢化合物inert gases 惰性气体saturate 浸透，饱和refractory metal 难熔金属ion 离子detrimental 有害的。

第一章晶体结构缺陷 defect, imperfection 点缺陷 point defect线缺陷 line defect, dislocation 面缺陷 interface defect体缺陷 volume defect 位错排列 dislocation arrangement位错线 dislocation line 刃位错 edge dislocation螺位错 screw dislocation 混合位错 mixed dislocation晶界 grain boundaries 大角度晶界 high-angle grain boundaries小角度晶界 tilt boundary, 孪晶界 twin boundaries位错阵列 dislocation array 位错气团 dislocation atmosphere位错轴 dislocation axis 位错胞 dislocation cell位错爬移 dislocation climb 位错聚结 dislocation coalescence位错滑移 dislocation slip 位错核心能量 dislocation core energy位错裂纹 dislocation crack 位错阻尼 dislocation damping位错密度 dislocation density 原子错位 substitution of a wrong atom 间隙原子 interstitial atom 晶格空位 vacant lattice sites间隙位置 interstitial sites 杂质 impurities弗伦克尔缺陷 Frenkel disorder 肖脱基缺陷 Schottky disorder主晶相 the host lattice 错位原子 misplaced atoms缔合中心 Associated Centers. 自由电子 Free Electrons电子空穴 Electron Holes 伯格斯矢量 Burgers克罗各-明克符号 Kroger Vink notation 中性原子 neutral atom原子质量单位 Atomic mass unit (amu) 原子数 Atomic number原子量 Atomic weight 波尔原子模型 Bohr atomic model键能 Bonding energy 库仑力 Coulombic force共价键 Covalent bond 分子的构型 molecular configuration电子构型 electronic configuration 负电的 Electronegative正电的 Electropositive 基态 Ground state氢键 Hydrogen bond 离子键 Ionic bond同位素 Isotope 金属键 Metallic bond摩尔 Mole 分子 Molecule泡利不相容原理 Pauli exclusion principle 元素周期表 Periodic table原子 atom 分子 molecule分子量 molecule weight 极性分子 Polar molecule量子数 quantum number 价电子 valence electron范德华键 van der waals bond 电子轨道 electron orbitals点群 point group 对称要素 symmetry elements各向异性 anisotropy 原子堆积因数 atomic packing factor(APF)体心立方结构 body-centered cubic (BCC) 面心立方结构 face-centered cubic (FCC)布拉格定律bragg’s law配位数 coordination number晶体结构 crystal structure 晶系 crystal system晶体的 crystalline 衍射 diffraction中子衍射 neutron diffraction 电子衍射 electron diffraction晶界 grain boundary 六方密堆积 hexagonal close-packed (HCP)鲍林规则Pauling’s rules NaCl型结构 NaCl－type structureCsCl型结构 Caesium Chloride structure 闪锌矿型结构 Blende-type structure 纤锌矿型结构 Wurtzite structure 金红石型结构 Rutile structure萤石型结构 Fluorite structure 钙钛矿型结构 Perovskite-type structure尖晶石型结构 Spinel-type structure 硅酸盐结构 Structure of silicates岛状结构 Island structure 链状结构 Chain structure层状结构 Layer structure 架状结构 Framework structure滑石 talc 叶蜡石 pyrophyllite高岭石 kaolinite 石英 quartz长石 feldspar 美橄榄石 forsterite各向同性的 isotropic 各向异性的 anisotropy晶格 lattice 晶格参数 lattice parameters密勒指数 miller indices 非结晶的 noncrystalline多晶的 polycrystalline 多晶形 polymorphism单晶 single crystal 晶胞 unit cell电位 electron states (化合)价 valence电子 electrons 共价键 covalent bonding金属键 metallic bonding 离子键 Ionic bonding极性分子 polar molecules 原子面密度 atomic planar density衍射角 diffraction angle 合金 alloy 配位数 coordination number粒度,晶粒大小 grain size 显微结构 microstructure显微照相 photomicrograph 扫描电子显微镜 scanning electron microscope (SEM)透射电子显微镜 Transmission electron microscope (TEM)重量百分数 weight percent 四方的 tetragonal 单斜的 monoclinic第二章晶体结构缺陷-固溶体固溶度 solid solubility 间隙固溶体 interstitial solid solution金属间化合物 intermetallics 转熔型固溶体 peritectic solid solution无序固溶体 disordered solid solution取代型固溶体 Substitutional solid solutions非化学计量化合物 Nonstoichiometric compound第三章熔体结构熔体结构 structure of melt 过冷液体 supercooling melt玻璃态 vitreous state 软化温度 softening temperature粘度 viscosity 表面张力 Surface tension介稳态过渡相 metastable phase 组织 constitution淬火 quenching 退火的 softened玻璃分相 phase separation in glasses 体积收缩 volume shrinkage第四章固体的表面与界面表面 surface 界面 interface 惯习面 habit plane同相界面 homophase boundary 异相界面 heterophase boundary晶界 grain boundary 表面能 surface energy小角度晶界 low angle grain boundary 大角度晶界 high angle grain boundary 共格孪晶界 coherent twin boundary 晶界迁移 grain boundary migration错配度 mismatch 驰豫 relaxation重构 reconstuction 表面吸附 surface adsorption表面能 surface energy 倾转晶界 titlt grain boundary扭转晶界 twist grain boundary 倒易密度 reciprocal density共格界面 coherent boundary 半共格界面 semi-coherent boundary非共格界面 noncoherent boundary 界面能 interfacial free energy应变能 strain energy 晶体学取向关系 crystallographic orientation 第五章相图相图 phase diagrams 相 phase 组分 component 组元 compoonent 相律 Phase rule 投影图 Projection drawing浓度三角形 Concentration triangle 冷却曲线 Cooling curve成分 composition 自由度 freedom相平衡 phase equilibrium 化学势 chemical potential热力学 thermodynamics 相律 phase rule吉布斯相律 Gibbs phase rule 自由能 free energy吉布斯自由能 Gibbs free energy 吉布斯混合能 Gibbs energy of mixing 吉布斯熵 Gibbs entropy 吉布斯函数 Gibbs function热力学函数 thermodynamics function 热分析 thermal analysis过冷 supercooling 过冷度 degree of supercooling杠杆定律 lever rule 相界 phase boundary相界线 phase boundary line 相界交联 phase boundary crosslinking共轭线 conjugate lines 相界有限交联 phase boundary crosslinking相界反应 phase boundary reaction 相变 phase change相组成 phase composition 共格相 phase-coherent金相相组织 phase constentuent 相衬 phase contrast相衬显微镜 phase contrast microscope 相衬显微术 phase contrast microscopy 相分布 phase distribution 相平衡常数 phase equilibrium constant相平衡图 phase equilibrium diagram 相变滞后 phase transition lag相分离 phase segregation 相序 phase order相稳定性 phase stability 相态 phase state相稳定区 phase stabile range 相变温度 phase transition temperature相变压力phase transition pressure 同质多晶转变polymorphic transformation同素异晶转变allotropic transformation 相平衡条件phase equilibrium conditions显微结构 microstructures 低共熔体 eutectoid不混溶性 immiscibility第六章扩散下坡扩散 Downhill diffusion 互扩散系数 Mutual diffusion渗碳剂 carburizing 浓度梯度 concentration gradient浓度分布曲线 concentration profile 扩散流量 diffusion flux驱动力 driving force 间隙扩散 interstitial diffusion自扩散 self-diffusion 表面扩散 surface diffusion空位扩散 vacancy diffusion 扩散偶 diffusion couple扩散方程 diffusion equation 扩散机理 diffusion mechanism扩散特性 diffusion property 无规行走 Random walk达肯方程 Dark equation 柯肯达尔效应 Kirkendall equation本征热缺陷 Intrinsic thermal defect 本征扩散系数 Intrinsic diffusion coefficient 离子电导率 Ion-conductivity 空位机制 Vacancy concentration第七章相变过冷 supercooling 过冷度 degree of supercooling晶核 nucleus 形核 nucleation形核功 nucleation energy 晶体长大 crystal growth均匀形核 homogeneous nucleation 非均匀形核 heterogeneous nucleation形核率 nucleation rate 长大速率 growth rate热力学函数 thermodynamics function临界晶核 critical nucleus 临界晶核半径 critical nucleus radius枝晶偏析 dendritic segregation 局部平衡 localized equilibrium平衡分配系数 equilibrium distributioncoefficient 有效分配系数 effective distribution coefficient成分过冷 constitutional supercooling 引领（领现相） leading phase共晶组织 eutectic structure 层状共晶体 lamellar eutectic伪共晶 pseudoeutectic 离异共晶 divorsed eutectic表面等轴晶区 chill zone 柱状晶区 columnar zone中心等轴晶区 equiaxed crystal zone 定向凝固 unidirectional solidification 急冷技术 splatcooling 区域提纯 zone refining单晶提拉法 Czochralski method 晶界形核 boundary nucleation位错形核 dislocation nucleation 晶核长大 nuclei growth斯宾那多分解spinodal decomposition 有序无序转变disordered-order transition马氏体相变 martensite phase transformation 马氏体 martensite第八、九章固相反应和烧结固相反应 solid state reaction 烧结 sintering烧成 fire 合金 alloy再结晶 Recrystallization 二次再结晶 Secondary recrystallization成核 nucleation 结晶 crystallization子晶，雏晶 matted crystal 耔晶取向 seed orientation异质核化heterogeneous nucleation 均匀化热处理homogenization heat treatment铁碳合金 iron-carbon alloy 渗碳体 cementite铁素体 ferrite 奥氏体 austenite共晶反应 eutectic reaction 固溶处理 solution heat treatment。

Unit2 Silicate StructuresAtomic arrangement in hundreds of silicates having complex chemical compositions have in their basic structures a beautiful simplicity and order. At the same time the details of many of the silicate structures are complex and difficult to illustrate without three-dimensional models, and we will not attempt to give precise structure information.The radius ratio for Si-O is 0.29, corresponding to tetrahedral coordination, and four oxygen ions are almost invariably arrayed around a central silicon. With a bond strength of 1, oxygen ions may be coordinated with only two silicon atoms in silica; this low coordination number makes close-packed structures impossible for SiO2, and in general silicates have more open structures than those discussed previously. The SiO4tetrahedra can be linked in compounds such as corners are shared in several ways. There are four general types. In orthosilicates, [SiO4]4-, tetrahedra are independent of one another; in pyrosilicates ,[Si2O7]6- ions are composed of two tetrahedra with one corner shared; in metasilicates, SiO3(SiO3)n, two corners are shared to form a variety of ring or chain structures; in layer structures,(Si2O5)n, layers are made up of tetrahedra with three shares corners; in the various forms of silica, SiO2, four corners are shared.silica. Crystalline silica, SiO2, exists in several different polymorphic forms corresponding to different ways of combining tetrahedral groups with all corners shared. Three basic structures—quartz、tridymite、cristobalite—each exists in two or three modifications . The most stable forms are low quartz , below 573C ;high quartz ,573 to 867C;high tridymite,867 to 1470C;high cristobalite ,1470 to 1710C;and liquid ,above 1710C;and liquid , above 1710C .The low temperature modifications are distorted derivative structures of the basic high—temperature forms .(A derivative structure in the sense is one that can be derived from a basic structure of greater symmetry by distorting the structure in space rather than substituting different chemical species) We confine our attention to the basic high—temperature forms .High quartz has a structure which can be viewed as composed of connected chains of silica tetrahedra. Compared to the close packed structures discussed in the last section ,this is a relatively open structure; for example ,the density of quartz is 2.65g/cm3,compared with 3.59 for MgO and 3.96 for Al2O3 .However ,quartz has a greater density and closer packing than either of the high—temperature forms, tridymites(p=2.26)and cristobalite(p=2.32)Orthosilicates. This group includes the olivine minerals (forsterite,Mg2SiO4, and solid solutions with Fe2SiO4), the garnets, zircon, and the aluminosilicates-kyanite, silimanite, andalusite, and mullite. The structure of forsterite, Mg2SiO4, is similar to that found for chrysoberyl, Al2BeO4.The oxygen ions are nearly in a hexagonal close-packed structure with Mg2+ in octahedral and Si4+ in tetrahedral sites. (From a coordination point of view this assembly can also be considered an array of SiO4 tetrahedra with Mg2+ ions in the octahedral holes) .Each oxygen ion is coordinated with one Si4+ and three Mg2+ or with two Si4+.The structure of kyanite, Al2SiO5, consists of nearly cubic close-packed oxygen ions with Si4+ in tetrahedrl and Al3+ in octahedral sites. However, in the polmorphic forms andalusite and sillimanite have much more open structures, with SiO4tetrahedra coordinated with AlO6octahedral. Mullite, Al6Si2O13 , a common constituent of fired clay, has a structure similar to that of sillimanite (compare Al16Si8O40 and Al18Si6O39) .Pyrosilicate. Crystalline silicates containing Si2O76- ions are rare.Metasilicates. Silicates containing (SiO3)n2n-ions are of two types-cyclic or chain arrangements of the silica tetrahedra. Some of the discrete cyclic ions observed are the Si3O96- (such as in wollastonite, CaSiO3) and Si6O1812- (in bery1,BeAl2Si6O18) ions. Minerals with chain structures comprise a large group. Those with compositions corresponding to singlechain,(SiO3)n2n-, are the pyroxenes , and those with double chains,(Si4O11)n6n-,the amphiboles. The pyroxenes include enstatite, MgSiO3 ; dropsied ,MgCa(SiO3)2; spodumene,LiAl(SiO3)2; and jadeite .The amphiboles include tremolite ,(OH)2CaMg5(Si4O11)2, in which isomorhic substitution is widespread. The asbestos minerals are amphiboles. Framework Structures. Many important silicate structures are based on an infinite three dimensional silica framework. Among these are the feldspars and the zeolites. The feldspars are characterized by a framework formed with Al3+ replacing some of the Si4+ to make a framework with a net negative charge that is balanced by large ions in interstitial positions, that is,albite,NaAlSi3O8;anorthite,CaAl2Si2O8;orthoclase,KalSi3O8;celsian,BaAl2S i2O8; and the like .The network structures are similar in nature to the cristobalite structure ,with the alkali or alkaline earth ions fitting into interstices. Only the large positive ions are from feldspars; smaller ones that enjoy octahedral coordination are from chains or layer silicates.Much more open alumina-silica frameworks occur in the zeolites and ultramarines. In these compounds the framework is sufficiently open for there to be relatively large channels in the structure .The alkali and alkaline earth ions present can be exchanged in aqueous solutions, leading to there use as water softeners. In addition ,these channels can be used as molecularsieves for filtering mixtures on the basis of molecular size. The size of the channels in the network depends on the composition.硅酸盐结构单元原子排列在数以百计的硅酸盐有复杂的化学成分的基本结构一个美丽的简单性和秩序。

火工品INITIATORS&PYROTECHNICS文章编号：1003-1480（2021）02-0037-04几种起爆药的耐高温性能对比研究刘丽娟，刘斌（陕西应用物理化学研究所，陕西西安，710061）摘要：为了对比研究叠氮化银(SA)、斯蒂芬酸铅（LTNR）、高氯酸五氨基四唑二银（DATP）在200℃下的耐高温性能，以200℃为温度点，24h、50h、72h、100h为时间节点设计高温贮存试验。

收集高温试验样品，采用差示扫描量热法测试高温样品的热性能，采用X射线衍射测试高温样品的晶体结构，并对比分析高温试验前后样品的性能。

结果表明，LTNR仅能够在200℃高温箱内连续放置24h不发生分解，SA和DATP能够在200℃高温箱内连续放置100h保持性能稳定。

关键词：起爆药；叠氮化银；斯蒂芬酸铅；高氯酸五氨基四唑二银；热稳定性中图分类号：TQ563文献标识码：A DOI：10.3969/j.issn.1003-1480.2021.02.010Study on High Temperature Resistance Performance of Some Kinds of Primary ExplosivesLIU Li-juan，LIU Bin（Shaanxi Applied Physics and Chemistry Research Institute,Xi’an,710061）Abstract：In order to study the high temperature resistance property of SA,LTNR and DA TP under200℃,adopting200℃as the temperature points,24h,50h,72h and100h as the time nodes,the high temperature storage tests were carried out.The thermal performance and the crystal structure information of the samples before and after the high temperature storage tests were obtained by differential scanning calorimetry and X-ray diffraction,and the properties of samples before and after high temperature test were compared.All the test results show that LTNR can remain its intrinsic quality after being put in the ovens of 200℃for continuous24hours,and SA,DA TP can keep stable performances below200℃within100hours.Key words：Primary explosive；Silver azide；LTNR；DA TP；Thermal stability起爆药物理和化学性能的稳定性对武器系统和航空航天类火工装置在严苛作用环境下可靠作用有至关重要的影响[1-2]。

金砖御窑烧制所涉及的化学知识1.金砖御窑烧制需要了解陶瓷材料的化学成分和性质。

The firing of the royal kiln of the golden brick requires an understanding of the chemical composition and properties of ceramic materials.2.瓷器的釉料配方需要考虑各种化学原料的配比和反应条件。

The formulation of glazes for porcelain requires consideration of the proportions of various chemical raw materials and reaction conditions.3.了解氧化物在瓷器烧制过程中的化学变化对控制烧制温度和气氛有重要意义。

Understanding the chemical changes of oxides in thefiring process of porcelain is important for controlling the firing temperature and atmosphere.4.瓷器釉料的烧成过程涉及到各种化学反应和相变。

The firing process of glazes for porcelain involves various chemical reactions and phase transformations.5.熟悉瓷釉中的色谱化学知识可以帮助调配出不同颜色和特性的釉料。

Familiarity with the chromatography of glazes can help in formulating glazes of different colors and characteristics.6.了解金属氧化物的颜色和熔点的化学特性对于设计优质的釉料很重要。

氯化铵和硫酸铵生成焓与晶格能测定杨春;成文玉;王庆伦;刘晓莉;王桂香;杨津【摘要】A new inorganic chemistry experiment of “Determination of standard enthalpies of formation and lattice energies of ammonium chloride and ammonium sulfate” has been designed . To reduce the measurement error , temperature was measured by digital Beckman thermometer and the experimental data were passed to computer for drawing and linear regress by means of software Origin . As a result , the mass of ammonium chloride used for measurement of enthalpy of dissolution decreased to about 40% .The designing experiment on ammonium sulfate can cultivate the integrated ability ofstudents .Calculations of the lattice energies of ammonium chloride and ammonium sulfate based on their enthalpies of dissolution are introduced ,which can guide the students to research the relationship between the ionic crystal structures and physicochemical properties .%设计改进了一个新的无机化学实验“氯化铵和硫酸铵生成焓与晶格能的测定”。