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BaTiO3-Ba(Fe0.5Nb0.5)O3基陶瓷宽温介电温度稳定性探究引言陶瓷材料是一类具有广泛应用潜力的功能材料，其中介电陶瓷材料具有其特殊的电学性能和热学性能，因此在电子器件、传感器等领域得到了广泛的应用。
而介电陶瓷材料的温度稳定性是衡量其性能的关键指标之一，因此在材料设计和制备过程中，温度稳定性的探究显得尤为重要。
正文1. BaTiO3-Ba(Fe0.5Nb0.5)O3基陶瓷的制备方法BaTiO3-Ba(Fe0.5Nb0.5)O3基陶瓷通常接受固相反应法制备。
起首，按照化学计量比例将BaCO3、TiO2、Fe2O3和Nb2O5等原料混合匀称，并放置在高温炉中进行烧结反应。
随后，将烧结得到的块状样品进行研磨，进一步制备成所需的外形和尺寸的陶瓷材料。
2. BaTiO3-Ba(Fe0.5Nb0.5)O3基陶瓷的结构分析通过X射线衍射(XRD)分析表明，BaTiO3-Ba(Fe0.5Nb0.5)O3基陶瓷主要以钙钛矿相(BaTiO3)和硬铁矿相(Ba(Fe0.5Nb0.5)O3)为主。
此外，电子显微镜观察还发现陶瓷材料具有致密的微观结构和细小的晶粒大小。
3. BaTiO3-Ba(Fe0.5Nb0.5)O3基陶瓷的介电性能测试通过介电常数测试发现，BaTiO3-Ba(Fe0.5Nb0.5)O3基陶瓷在室温下具有较高的介电常数，且随着温度的提高介电常数逐渐减小。
同时，温度对介电损耗的影响也被测量和分析。
试验结果显示，随着温度的提高，介电损耗逐渐增加，表明在高温下材料的损耗较大。
4. BaTiO3-Ba(Fe0.5Nb0.5)O3基陶瓷的温度稳定性分析为了探究BaTiO3-Ba(Fe0.5Nb0.5)O3基陶瓷的温度稳定性，我们分别在低温(-50℃)和高温(200℃)下测量了其介电性能。
试验结果显示，在低温柔高温条件下，该陶瓷材料的介电常数变化较小，证明其具有较好的温度稳定性。
此外，介电损耗在低温柔高温下也保持在较低水平，进一步表明该材料具有良好的温度稳定性。
河南科技Henan Science and Technology 化工与材料工程总第812期第18期2023年9月Y2O3掺杂及烧结温度对SrTiO3基陶瓷电学性能的影响邹远来郭中正禄露玲聂贞海陈方健（安顺学院电子与信息工程学院，贵州安顺561000）摘要：【目的】获得综合电学性能良好的SrTiO3基电子功能陶瓷。
【方法】选取稀土氧化物Y2O3作掺杂剂，用典型电子陶瓷工艺制样，利用压敏电阻参数仪和数字电桥测试并结合扫描电镜（SEM)观察，探讨了Y2O3的掺杂量及烧结温度对SrTiO3基陶瓷电学性能和微观结构的影响规律。
【结果】随着Y2O3掺杂量从0.3mol.%渐增至1.8mol.%，陶瓷的压敏电压V1mA先减后增，非线性系数α逐渐减小，而相对介电常数εr和介电损耗tanδ均总体上呈升高趋势。
掺0.9mol.%Y2O3时，陶瓷综合电学性能较好。
提高烧结温度可获得更理想的微观结构并进一步提升电学性能，经1425℃、3h保温烧成、掺0.9mol.%Y2O3的SrTiO3基陶瓷的综合电学性能最优：V1mA=7.2V、α=10.8、εr=3.8×104、tanδ=2.1×10-2。
【结论】适量掺杂Y2O3并合理控制烧结温度，可使SrTiO3基陶瓷具有理想的微观结构，从而表现出优良的电学性能。
关键词：SrTiO3基陶瓷；Y2O3掺杂；烧结温度；电学性能中图分类号：TM283；TM534+.1文献标志码：A文章编号：1003-5168（2023）18-0070-05 DOI：10.19968/ki.hnkj.1003-5168.2023.18.015Effects of Y2O3Doping and Sintering Temperature on the ElectricalProperties of SrTiO3Based CeramicsZOU Yuanlai GUO Zhongzheng LU Luling NIE Zhenhai CHEN Fangjian （School of Electronics and Information Engineering,Anshun University,Anshun561000,China）Abstracts:[Purposes]This paper aims to obtain SrTiO3based electronic functional ceramics with good comprehensive electrical properties.[Methods]The samples were prepared by typical electronic ceramic processes with selected rare earth oxide Y2O3dopant,the effects of Y2O3doping amount and sintering temperature on the electrical properties and microstructures of SrTiO3based ceramics were investigated using varistor parameter instrument and digital bridge testing and scanning electron microscopy(SEM) observations.[Findings]With the doping amount of Y2O3gradually increases from0.3mol.%to1.8 mol.%,the breakdown voltage V1mA of the ceramics increases firstly and then decreases,and the nonlin⁃ear coefficientαgradually decreases,while the relative dielectric constantεr and dielectric loss tanδgenerally show an upward trend.The ceramics with0.9mol.%Y2O3doping possess better comprehensive electrical properties.Increasing the sintering temperature can obtain a more ideal microstructure and fur⁃ther improve the electrical properties.SrTiO3based ceramics doped with0.9mol.%Y2O3and sintered at收稿日期：2023-04-03基金项目：贵州省教育厅青年科技人才成长项目（黔教合KY字〔2019〕145号）；贵州省大学生创新创业训练计划项目（202110667006）。
第32卷第7期2004年7月华南理工大学学报(自然科学版)J ournal of South China University of Technology(Natural Science Edition )Vol.32 No.7J uly 2004文章编号:1000-565X (2004)07-0010-05使用铝电极的BaPbO 3陶瓷的PTCR 效应3李井润1 李志成2 徐永波2(1.电子科技大学中山学院,广东中山528402;2.中国科学院金属研究所沈阳材料科学国家(联合)实验室,辽宁沈阳110016)摘 要:为了研究开发具有低电阻率和正电阻温度系数(PTCR )的高居里点陶瓷材料,以BaCO 3和PbO 为原料制备了一组La 掺杂的陶瓷材料.实验发现,烧结的陶瓷样品在室温下具有极低的电阻率,且呈现出和金属导体一样的电导体特征;使用铝电极的BaPbO 3基陶瓷体表现出PTCR 特性,并且这种特性可以通过调整掺杂物的量进行改善.利用扫描电子显微镜和透射电子显微镜对陶瓷的微观结构进行了表征.微观结构分析表明,一薄层的烧结陶瓷表层为具有金属性质的正交结构BaPbO 3纳米相,并由此使其表现出极低的电阻率;具有PTCR 特性的陶瓷体内部是由具有畴结构的铁电相组成,所以除去烧结陶瓷表层后,喷镀铝电极的陶瓷体表现出正电阻温度效应.关键词:钡铅氧化物陶瓷;电阻率;正电阻温度系数;微观结构中图分类号:TN 305 文献标识码:A 收稿日期:2003-08-293基金项目:国家自然科学基金资助项目(59971069);国家重点基础研究资助项目(G 19990650) 作者简介:李井润(1964-),男,讲师,硕士,主要从事光学、半导体材料等的研究.E 2mail :jingrunli @ 正电阻温度系数(PTCR )材料是一种具有独特电导性质的半导体体系.当温度低于居里温度(T C )时,PTCR 材料的电阻率变化缓慢;当温度升至T C 后,陶瓷体的电阻率在一个极小的温度范围内可增加几个数量级.PTCR 热敏陶瓷的独特属性,使其在温控加热、恒温元件、瞬变电流产生器和环境温度指示器等[1～7]领域得到了广泛的应用.呈现PTCR 性质的材料一般为半导体钛酸盐(包括钡钛酸盐、铅钛酸盐和锶钛酸盐)陶瓷.BaPbO 3是典型的钙钛矿结构陶瓷.BaPbO 3基陶瓷材料因其具有低室温电阻,20世纪许多理论工作者把它作为一种潜在的超导体进行研究[8～14].一些学者认为,这些材料进行适当的掺杂后也可能显示PTCR 特性,但就笔者所知,目前关于BaPbO 3基陶瓷的PTCR 效应的研究尚未见报道.相对于BaTiO 3基陶瓷材料,BaPbO 3基陶瓷PTCR 材料具有更低的室温电阻率和更高的居里温度.如果BaPbO 3的PTCR 特性能够加以改善,在高温低压加热设备和大电流保护设备等方面的应用中将具有重要意义.本研究对La 2O 3掺杂的BaPbO 3基陶瓷的PTCR 特性进行探讨.1 实验部分1.1 陶瓷样品的制备以高纯BaCO 3和PbO 为原材料,按r (BaCO 3)∶r(PbO )=1∶1进行配料.加蒸馏水球磨混料24h ,在393K 干燥12h ,然后在1173K 温度下预烧合成2h.接着加入x (Al 2O 3)=0.03和x (SiO 2)=0.1(x为摩尔分数,下同),以便在低温时形成有助于烧结的液相并产生增强PTCR 效应的晶界结构.同时分别掺x =0.03,0.08,0.15的La 2O 3以得到呈PTCR 特性的半导体陶瓷.然后,球磨混合24h ,并在393K 温度下干燥12h.这些粉末用聚乙烯醇造粒后,压成尺寸为28mm ×17mm ×3.5mm 小片.烧结在1373K 的空气中完成.烧结后的样品制成尺寸为24mm ×15mm ×2.5mm 小片,并超声清洗和干燥.在两个24mm ×15mm 的面上喷铝形成电极.1.2 样品的导电性测量用欧姆计测量陶瓷的室温电阻.材料的电阻-温度(R-T)特性用计算机控制记录,加热速度为1K/min.1.3 微观结构分析陶瓷的微观结构采用附有X射线能量散射仪(EDS)的扫描电子显微镜(SEM)(型号为Cambridge S360)和J EM-2000-FXII透射电子显微镜(TEM)进行表征.SEM观察样品采用截面试样,磨平抛光后用5%HNO3+5%HCl+1%HF的水溶液进行浸蚀.掺杂x(La)=0.08的BaPbO3基陶瓷的TEM样品采用常规制备方法得到:从烧结陶瓷表面切取1mm 厚薄片,磨薄至80μm,挖坑至厚度约为40μm,最后用离子束减薄方法获得TEM试样.在制备TEM试样过程中,尽可能保留烧结陶瓷体的原始表面以便研究其微观结构和分析表面层具有室温低电阻的机制.2 实验结果和讨论2.1 La掺量对陶瓷导电性的影响与许多半导体陶瓷(如BaTiO3)通常呈灰色不同,掺杂La烧结样品呈黑色.实验发现,样品在室温下具有极低的电阻率,且呈现出和金属导体一样的电导体特征,其电阻小到用标准欧姆计都难以测量.然而,样品表层被磨去约20μm后,陶瓷体的电阻变得非常大,电阻值超出欧姆计的测量范围.当这种磨光的烧结陶瓷在两个主平面喷上铝电极后,低电阻率特征又显现出来,并且显示出很好的PTCR效应.例如,室温时其电阻介于1～5Ω之间,并随温度增大而增大;当加上12V直流电压时,测得陶瓷表面温度为(693±15)K.图1(a)给出了三种BaPbO3陶瓷的R-T特性曲线.从图中可看出,当温度大于某一温度(居里温度)时,电阻急剧上升.这表明,掺杂BaPbO3陶瓷显示出良好的PTCR效应.图1 (b)为图1(a)中温度低于673K段的R-T曲线.掺x(La)=0.15陶瓷的R-T曲线为非平滑曲线,这可能是由于测量误差或其他原因所致.三种类型的陶瓷有相近的居里温度,约为643K.从两图中可以看出,在低于居里温度T C时,电阻随掺入La的量增大而增大;在高于居里温度T C时,电阻的增大与掺杂物的量有关.比较它们的低温区(<T C)和高温区(>T C)的图1 三种BaPbO3陶瓷的R-T曲线Fig.1 R-T curves of the three BaPbO3ceramics电阻增大率,可以得出以下结果:(1)掺x(La)=0.03的陶瓷,具有最小的低温电阻率,而在高于T C后表现出最小的电阻增大率;(2)掺x(La)=0.15的陶瓷,具有最大低温电阻率,高于其T C时呈现中等程度的电阻增大率.(3)掺x(La)=0.08的陶瓷,在低温下有中等程度的电阻,但高于T C时,存在最大的电阻增大率.以上分析表明,可以通过调整掺杂物的量来改善BaPbO3基陶瓷的PTCR效应.2.2 BaPbO3基陶瓷的微观结构为进一步了解烧结陶瓷显示金属性的行为,以及在磨去其表层后表现出的半导体特性,本研究对BaPbO3陶瓷的微观结构进行了探讨.图2(a)为掺x(La)=0.08陶瓷的近表层的SEM照片.从图中可以看出,这些晶粒有两种不同的形状和衬度.产生不同衬度的原因可能是这两种晶粒在腐蚀过程中具有不同抗蚀能力所致.从图中还可看到,陶瓷表面几乎是由白色的板条状晶粒组成.板条状晶粒的平均厚11 第7期李井润等:使用铝电极的BaPbO3陶瓷的PTCR效应度约为2μm .然而,在样品中心,这种板条状晶粒的数量极少(见图2(b )).结合其电性质和微观结构,这些白色板条状晶粒极可能是表层具有非常低的电阻率和具有金属特性的原因,并且陶瓷体内的等轴晶粒对产生PTCR 效应起关键作用.图2 掺杂x (La )=0.08烧结BaPbO 3陶瓷的SEM 照片Fig.2 SEM photographs of the as 2sintered x (La )=0.082doped BaPbO 3ceramic图3给出了在图2(a )中分别用A 和B 标记区域的EDS 结果.区域B 的氧含量比区域A 的更高,并且,在区域B 中测出铝元素的存在,但在区域A 中并未检测到;区域A 中的Ba 含量高于区域B ;La 含量因太少而无法检测到.图4为烧结BaPbO 3陶瓷的TEM 明场像.从两明场像图中可看出,在这些区域中存在两种类型的组织结构:其中一个区域(用D 标识)晶粒是典型的铁电体陶瓷的微观结构.图4(a )中的插入选区电子衍射谱(SAED )是晶粒D 中得到的.另一种类型的结构呈现为图4(a )和图4(b )中用C 标识的区域,它们具有比区域D 更加细小的晶粒.图4(c )为图4(b )中区域C 的放大图像,显示出纳米晶粒,而插入的SAED 谱表现为环状.从图2中的SEM 照片来看,样品近表层(图2(a ))甚至样品中心(图2(b ))都含有两种衬度及形态的组织;图4的TEM 观察结果中也存在两种组织,说明两种方法获得的结果相吻合.同时图4TEM 观察结果中D 区具有铁电畴结构,应该是样品体现PTCR 效应的贡献者,可以推断出是样品中心区的等轴晶(即图2(a )中的B 所示晶粒).也就是说,图4中的C 区域应该与图2(a )中A 区域组织相对应,即表明样品表层的低电阻特性来自图4中的C 区域的细小晶粒.根据Bragg 规则:R i d i =L λ.式中:R i 为第i 个衍射环到透射点〈000〉之间的距离;d i 为从衍射环中计算得到的晶格常数面间距;L 为相机的长度(L =80cm );λ为波长(当加速电压为120kV 时λ为0.251nm ).从SAED 衍射环计算得到的晶格常数面间距如表1所示.正如一些学者[8～10]所报道的,BaPbO 3陶瓷在室温下的结构是正交结构.表1还给出了两组根据K im 等[13]和Moussa 等[14]报道的晶格参数计算得到的晶格常数面间距.晶格常数面间距可以采用下列的公式进行计算:1d hkl=h 2a2+k 2b2+l 2c2.式中:d hkl 为{hkl }晶面的面间距;a ,b ,c 为晶体BaPbO 3的晶格常数.Moussa 等[13,14]的报道中,晶格常数分别为:a =6.0299,b =8.5094,c =6.0694.结合本实验结果,本研究调整这些参数顺序为:a =6.0694,b =8.5094,c =6.0299.图3 掺杂x (La )=0.08烧结BaPbO 3陶瓷的EDS 结果Fig.3 EDS results of the as 2sintered x (La )=0.082dopedBaPbO 3ceramic21华南理工大学学报(自然科学版)第32卷图4 掺杂x(La)=0.08烧结BaPbO3陶瓷的TEM照片观察结果Fig.4 TEM observations of the as2sintered x(La)=0.082doped BaPbO3ceramic表1 晶格常数面间距对比Table1 Contrast of interplanar distance for lattice constant本实验结果R i/mm d i/nm 根据K im等人结果的计算值d hkl/nm根据Moussa等人结果的计算值d hkl/nm晶面指数hkl4.750.422740.425470.425470025.250.382470.382050.382191116.500.308920.301510.301510200.303170.30345200 8.000.251000.246900.247052020.246000.24600022 9.500.211370.213780.213882200.212740.21274004 10.000.20080.195560.19558123 10.750.186790.186170.186191310.186960.18710311 从表1中可看出,本文从SAED环中计算得到的晶面间距与文献[13,14]报道的从晶格参数中计算得到的晶面间距吻合非常好.这说明本实验中的陶瓷体表层为正交结构的BaPbO3.因为纯BaPbO3氧化物具有极低的电阻率(约10-3Ω·cm)[15,16],这表明陶瓷的表层为BaPbO3“金属性”导体.同时也证明,本文中研究的由金属性BaPbO3状态组成的烧结陶瓷表层是决定烧结陶瓷有极低电阻率的根本原因.结合图4和图2得出,在图2中显示的板条状晶粒应是由图4中显示的纳米晶粒组成的.这表明这些板条状晶粒应该是“金属”特性相.而这些板条状晶粒只存在于烧结陶瓷表面而并不存在于其内部(如图2(b)所示).在样品近表层存在的金属性晶粒必是烧结陶瓷显示极低电阻率的原因.2.3 PTCR效应讨论由TEM的观察结果得出,烧结陶瓷体内部主要由具有畴结构的组织组成.引进的施主搀杂元素La 置换了钙钛矿结构BaPbO3中的Ba位置.由于在八面体结构中La和Ba的离子半径差(R Ba= 149×10-12m,R La=117×10-12m)使晶体存在弹性变形而产生极化,从而在TEM中可观察到畴结构.另一方面,施主搀杂元素的加入,也可能形成Ba空位和使材料半导体化.少量氧化铝和二氧化硅的加入,一方面能在烧结过程中形成玻璃相,有助于吸收有害元素(如Na等);另一方面冷却后玻璃相存在于晶粒界面能更好地提高材料的高温电阻,从而提高材料的PTCR效应[17].所以,在去除表面低电阻层后,陶瓷显示出半导体特性和PTCR效应.3 结束语烧结BaPbO3陶瓷表面一薄层具有极低的电阻率,其原因是这一薄层由具有“金属”特性的BaPbO3组成.除去表层约20μm后,La搀杂BaPbO3陶瓷表现为低电阻率和半导体行为,并具有PTCR效应.当在陶瓷中加上12V的直流电压时,陶瓷表层温度约为(693±15)K.搀杂量对性能影响的规律为:掺杂x (La)=0.08的陶瓷表现出最好的PTCR效应;更低的搀杂量形成更小的室温电阻率陶瓷但PTCR效应更差;更高的搀杂量产生更大的室温电阻率但也不能获得更好的PTCR效应.参考文献:[1] Thornton G,Jacobson A J.Podwer neutron2diffraction deter2mination of structure of BaPbO3at4.2K[J].Mater Res Bull,1976,11(7):837-841.31 第7期李井润等:使用铝电极的BaPbO3陶瓷的PTCR效应[2] Swilam M N,Gadalla A M.Decomposition of barium titanyloxalate and assessment of barium2titanate produced at various temperatures[J].Brit Ceram Trans J,1975,74(5):159-163.[3] Howng W Y,McLutcheon C.Electrical2properties of semi2conductring BaTiO3by liquid2phase sintering[J].Am Ceram Soc Bull,1983,62(2):231-236.[4] Beauger A,Mutin J C,Niepce J C.Synthesis reaction ofmetatitanate BaTiO3(1):E ffect of the gaseous atmosphere upon the thermal evolution of the system BaCO32TiO2[J].J Mater Sci,1983,18(10):3041-3046.[5] Y amada A,Chiang Y M.Nature of cation vacancies formed tocompensate donors during oxidation of barium2titanate[J].J Am Ceram Soc,1995,78(4):909-914.[6] Lin M H,Lu H Y.Site2occupancy of yttrium as a dopant inBaO2excess BaTiO3[J].Mater Sci Eng A,2002,335(1-2):101-108.[7] K ennedy B J,Hunter B A.High2temperature phases of Sr2RuO3[J].Phys Rev B,1997,58(2):653-658.[8] Sleight A W,Gilson J L,Bierstedt P E.High2temperature su2perconductivity in BaPb1-x Bi x O3system[J].Solid State Commun,1975,17(1):27-28.[9] K han Y,Nahm K,Posenberg M.Superconductivity and semi2conductor2metal phase2transition system BaPb1-x Bi x O3[J].Phys Status Sol(a),1977,39(1):79-88.[10] Oda M,Hidaka Y,K atsui A,et al.Structural phase2transi2tion in superconducting BaPb0.75Bi0.25O3[J].Solid StateCommun1985,55(5):423-426.[11] Ritter H,Ihringer J,Maichle J K,et al.The crystal2structureof the prototypic ceramic superconductor BaPbO3:An X2ray and neutron2diffraction study[J].Z Pphys B,1989,75(3):297-302.[12] Marx D T,Radaeli P G,Jorgensen J D,et al.Metastable behav2ior of the superconducting phase in the BaPb1-x Bi x O3system[J].Phys Rev B,1992,46(2):1144-1156.[13] K im J Y,Lee S Y,Y ang I S,et al.Raman and infraredspectroscopy of Y Ba2Cu3O72delta2BaPbO3composites[J].Physica C,1998,308(1-2):60-66.[14] Moussa S M,K ennedy B J,Vogt T.Structural variants inABO3type perovskite oxides:On the structure of BaPbO3[J].Solid State Commun,2001,119(8-9):549-552. [15] Hiroshi I,Shigeru H.E lectrical properties of BaPbO3ceramics[J].Solid State E lectron,1966,9(10):921-925.[16] Cava R J,Takagi H,Krajewski J J,et al.Oxygen2deficientbarium lead oxide perovskites[J].Phys Rev B,1993,47(17):11525-11528.[17] Ihrig H,K ierk M.Visualization of the grain2boundary po2tential barriers of PTC2type BaTiO3ceramics by cathodolu2minescence in an electron2probe microanaly2zer[J].ApplPhys Lett,1979,35(1):307-309.P TCR Eff ect of Ba PbO3Ce ra mic wit h Al Elect rodeLi J ing2run1 Li Zhi2cheng2 Xu Y ong2bo2(1.Zhongshan College,Univ.of Electronic Science and Tech.of China,Zhongshan528402,Guangdong,China;2.Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy ofSciences,Shenyang110016,Liaoning,China)A bst ract:A series of La2doped ceramics was prepared with the materials of BaCO32PbO powders in order to obtain the ceramics with high Curie point,low electrical resistivity and PTCR(Positive Temperature Coefficient of Resistivi2 ty).It is found from experiments that as2sintered ceramics are of very low electrical resistivities and show the same conductor feature as metal conductors,that the BaPbO32based ceramic body with Al electrode displays the PTCR char2 acteristic which can be improved by adjusting the La content.Microstructures of the ceramics were then analyzed by us2 ing scanning electron microscopy and transmission electron microscopy.The analytical results reveal that the low resis2 tivity of the ceramic surface layer results from the nanosized BaPbO3orthorhombic phase which is of metallic proper2 ties,and that the ceramic interior is composed of the ferroelectric phase with domain structures,thus causing the PTCR effect in the ceramic body with Al electrode when the surface layer is removed.Ke y wor ds:BaPbO3ceramic;electrical resistivity;positive temperature coefficient of resistivity;microstructure 41华南理工大学学报(自然科学版)第32卷。
添加SrO-B2O3-SiO2玻璃对BaxSr1-xTiO3基陶瓷介电性能的影响添加SrO-B2O3-SiO2玻璃对BaxSr1-xTiO3基陶瓷介电性能的影响引言：陶瓷材料是一类具备特殊物理化学性能的材料，其中包括介电陶瓷。
介电陶瓷在电子器件中有着广泛的应用，如电容器等。
BaxSr1-xTiO3基陶瓷是其中的一种，具有优良的介电性能。
为了改善BaxSr1-xTiO3陶瓷的介电性能，可以通过添加SrO-B2O3-SiO2玻璃进行调控。
本文主要介绍添加SrO-B2O3-SiO2玻璃对BaxSr1-xTiO3基陶瓷介电性能的影响。
一、SrO-B2O3-SiO2玻璃的作用机制SrO-B2O3-SiO2玻璃是一种常用的无定形辅助相，被广泛用于陶瓷材料中。
在BaxSr1-xTiO3陶瓷中添加SrO-B2O3-SiO2玻璃能够通过晶界相互作用提高陶瓷的致密性和晶界结合力。
此外，SrO-B2O3-SiO2玻璃还可以改变陶瓷的晶界组成，调节陶瓷的晶界能带结构和能带宽度，从而影响陶瓷的电学性能。
二、添加SrO-B2O3-SiO2玻璃对BaxSr1-xTiO3基陶瓷介电性能的影响实验结果表明，适量添加SrO-B2O3-SiO2玻璃能够显著提高BaxSr1-xTiO3基陶瓷的介电常数。
这是因为SrO-B2O3-SiO2玻璃能够填补陶瓷颗粒间的孔隙，提高陶瓷的致密性，减少了界面电阻和体积效应。
此外，SrO-B2O3-SiO2玻璃还能与BaxSr1-xTiO3基陶瓷形成良好的界面结合，提高陶瓷的晶界结合力和机械强度。
添加SrO-B2O3-SiO2玻璃对BaxSr1-xTiO3基陶瓷的介电损耗也有一定的影响。
当SrO-B2O3-SiO2的含量较低时，陶瓷的介电损耗较低；当SrO-B2O3-SiO2的含量过高时，陶瓷的介电损耗会增大。
因此，在实际应用中需要选择适当的添加量，以在满足介电性能要求的同时降低介电损耗。
三、结构与性能的关系探究通过X射线衍射和扫描电子显微镜观察，可以发现添加SrO-B2O3-SiO2玻璃后陶瓷的晶粒尺寸更加均匀，晶界更加清晰。
y BaT iO 3陶瓷的PT C 效应莫文玲1, 张庆军2, 胡林彦3, 沈 毅2(1.河北理工大学信息学院,河北唐山 063009;2.河北理工大学材料学院,河北唐山 063009;3.中国科学院大连化学物理研究所,辽宁大连 116023)摘 要:对不同掺杂的BaT iO 3基陶瓷的电性能、界面形态、氧元素分布特点以及电畴结构等进行研究发现:瓷体半导化速度很快,烧成温度是影响瓷体半导化速度的最重要因素;氧在晶粒晶界的偏析,并且对势垒的形成有重要作用;样品掺杂的元素不同,电畴结构会发生一定变化,畴结构和电阻起跳性存在一定关系.关键词:PT C 效应;晶界;BaT iO 3陶瓷;电畴中图分类号:T Q 174 文献标识码:A 文章编号:1000 5854(2006)04 0419 04材料的微观结构决定材料的性能,对PTC 材料微观结构和PT C 机理的研究是PTC 陶瓷材料发展的关键.瓷体的半导化进程[1]、晶界的性质[2,3]和畴结构[4~6]等对陶瓷性能有着至关重要的影响.要想深入研究PT C 机理,必需首先对陶瓷的半导化、势垒的形成以及影响半导化和势垒的因素进行研究.本文中,笔者通过系统的实验和电子显微镜能谱分析对上述内容进行了较为细致的研究,并且在实验的基础上得到一些有意义的结论.1 实验分析与讨论1.1 晶粒半导化过程制备施主掺杂量较高的BaTiO 3基系列陶瓷,瓷体的制备工艺流程如图1所示.施主选择Y 2O 3,受主选择MnO 2.不同施、受主掺杂量样品的室温电阻如图2所示.可见,随着掺杂量的不同,陶瓷的室温电阻波动很大,但当施主Y 2O 3掺杂量在1.10%~1.35%之间、受主M n 掺杂量在0.07%时,可以得到室温电阻普遍较低的陶瓷样品,其室温电阻最低可达35 .试验还表明一个趋势,随着施主掺杂量的增加,要想得到室温电阻低的样品,需同时增加受主的掺杂量,说明施主和受主是2个互相制约的因素,只有它们的含量匹配合适,才能得到室温电阻低的陶瓷材料.烧成M n 掺杂量为0.07%、不同Y 2O 3掺杂量的试样,烧成温度为1300 ,不保温且急冷.测定电阻,得到阻温曲线如图3所示,可见,当Mn 掺杂量为0.07%,Y 2O 3掺杂量为1.20%时,材料的PTC 特性最好.室温电阻曲线(图2)表明,该试样的室温电阻为112 ,尽管不是这组试样中最低的,但室温电阻值很小说明材料已经充分半导化.该组试样在10%FH 中腐蚀6min 后的显微形貌如图4所示,可以看出,样品的结晶比较规则,晶粒大小比较均匀,晶粒呈柳叶状,形成簇状结晶.与保温的试样相比,该试样晶粒上看不到明显的晶棱,说明虽然晶粒有一定的体积,但其结晶并不完整.所以,对于高掺杂量的陶瓷,没有高温阶段的保温可以得到室温电阻较低的瓷体,但由于结晶不好,瓷体的PTC 性能不可能太好.y 收稿日期:20060227基金项目:国家自然科学基金资助项目(50444019);河北省自然科学基金资助项目(E2005000433)作者简介:莫文玲河北理工大学副教授,硕士,主要从事材料物理方面的研究.第30卷第4期2006年 7月河北师范大学学报(自然科学版)Jour nal of Hebei Normal U niversit y (N atural Science Edition)Vol.30No.4Jul.2006实验表明,陶瓷的半导化应该是热力学控制的过程,与烧成温度密切相关,且半导化的反应速度很快,只要温度能够达到半导化反应的要求,使半导化反应能克服反应的势垒,陶瓷体就能很快半导化;而其电阻起跳性差则说明PTC 效应来源于高温和降温阶段物质在晶界的聚集,这个过程的进行相对缓慢,应该属于动力学控制的过程,需要在高温和降温阶段的适当温度下进行一定时间的保温.1.2 晶界氧元素选择具有良好PTC 性能的陶瓷试样,对其晶界微区和晶粒内部微区进行透射电镜能谱分析,加速电压为200kV,得到2个区域的能谱曲线,如图5所示.可见,晶界和晶粒内部成分的显著差别是氧含量不同,晶界氧含量为10.46%,晶粒内部氧含量为4.00%.图谱分析表明,晶界的氧含量明显高于晶粒内部,甚至超过了施主受主含量的总和.所以,对于属于晶界效应的PTC 效应来说,氧对陶瓷晶界的电性能具有重要的影响.这些氧可能的来源有3个:晶粒氧挥发,通过半导化过程从晶粒内部脱离出来;高温烧成时空气中的氧对晶界杂质的氧化;具有高表面能的晶界对氧的吸附.此外还发现,晶界的Ba 含量要比晶粒内部小,这可能是由于晶界Ba 的缺位浓度大造成的.1.3 氧对晶界势垒的影响对瓷体进行能谱分析表明,氧元素在晶界的分布远远超过晶粒内部.氧带负电荷,分布在晶界上,形成层状结构:负电荷聚集在界面中心,周围是正电荷,这些正电荷是偏析在晶界的受主等阳离子杂质,它们以晶界为中心对称分布.正、负电荷的数量相差很小,保持了界面的电中性.电中性的界面对载流子阻碍很小,宏观上不显现出电导势垒的存在.电导势垒很小,陶瓷体的电阻也较小,这样可以很好地解释低于居里温度时瓷体电阻很低的现象.文献[7]表明,钙钛矿结构氧化物温度升高时能释放出部分氧,温度降低时又能把氧吸收回去,即氧呼吸现象.在多次循环过程中基本晶格结构不会破坏,这与PT C 陶瓷的PTC 特性相同.随着温度升高,420河北师范大学学报(自然科学版)第30卷瓷体电阻增大,随着温度回落,瓷体的电阻又降低,这样的循环可以重复进行,而瓷体的结构不被破坏.图6 掺Y 样品的电畴形貌1.4 电畴形貌施主掺杂BaTiO 3半导材料的PTC 效应与电畴结构密切相关.对试样进行TEM 观察,可以看到,电畴的形貌及空间分布很复杂,不仅单晶内多畴,即使在多晶内部也是多畴交错.对不同掺杂种类的瓷体进行观察,发现掺杂物不同,电畴的形貌也不同.Y,M n 掺杂的样品,电畴形貌如图6所示,样品中有大量的90 电畴,180电畴则较少,电畴呈鱼骨状.图6a 为晶粒内部较大面积的90 畴,部分畴的条纹呈W 形,这样的电畴之间的交角偏离了90 ,可以形成其他角度的电畴.图6b 为宽度较大的电畴,形成梭形的并排结构,其相邻区域没有其他畴结构.Sr,Cu 掺杂的样品,电畴的形貌呈正交网格状(如图7所示),180 电畴的量增多.图7a 是晶粒表面上的电畴,电畴的发育比较规则,有一定宽度,互相平行的90 畴构成一小区域,不同小区域的畴互相交叉,交角为90 .图7b 是晶粒内部的电畴,90 畴同样形成不同的小区域,相邻2个小区域的电畴在交界处互相垂直,构成直角框架式的结构,2个晶粒的电畴可以在晶界处相交,构成180 畴.研究表明,90 电畴的结构与降温速度、陶瓷的缺陷和杂质有很大关系[8].不同离子的半导掺杂,由于离子尺寸不同,会造成不同的应变和应力,导致畴结构出现差别.不同畴结构对电子迁移的阻力不同.图7 掺Sr 样品的电畴形貌通过对试样电性能的对比测试发现,正交网格状的畴结构有利于陶瓷的电阻突跳(如图8所示,其中a 为Sr,Cu 掺杂的样品,b 为Y,M n 掺杂的样品).对晶界进行选区电子衍射(SAD),发现衍射图中(图9)同时具有非晶斑和单晶斑,说明晶界区存在玻璃相.从单晶斑点的排列来看,同一方向的排列间距有微小差别,且单晶斑点的强度也出现差别,说明衍射图中并不单单存在一套格子排列,而是在晶界形成了一种规则的多晶层状结构.421第4期莫文玲等:BaT iO 3陶瓷的PT C 效应3 结 论陶瓷的半导化为热力学控制的过程,只要温度能够达到半导化反应的要求,陶瓷体就能很快半导化;而PTC 效应则来源于晶界的形成,这个过程相对较慢,属于动力学控制的过程.晶界和晶粒内部成分的最大差别是氧含量,晶界的氧含量明显高于晶粒内部,且超过施主及受主含量的总和.PTC 效应属于晶界效应,氧对陶瓷晶界的电性能具有重要的影响.陶瓷中掺杂物不同陶瓷电畴的形貌也不同.Y,M n 掺杂样品的电畴呈鱼骨状,Sr,Cu 掺杂样品的电畴呈正交网格状.正交网格状的畴结构有利于陶瓷的电阻突跳.参考文献:[1] DESU S B.Interfacial effects in perovskites [J].Key Eng ineering M aterials,1992,66 67:375 420.[2] HEY WAN G W.Resistiv ity anomaly in doped bor ium titanat e [J].J A m Ceram Soc,1964,47(10):484.[3] 赵世玺,刘韩星.钛酸钡陶瓷晶界结构、偏析与性能[J].功能材料,2000,31(3):233 236.[4] ROSEM AN R D.Hig h temperature pding effects o n conducting barium titanate cer amics [J].F er roelectrics,1998,215:31 45.[5] BU CHANA N R C,KI M J,RO SEM AN R D.M icrost ructural effects on conductiv ity in donor do ped BaT iO 3[J].Ferroelectrics,1996,177:255 271.[6] L IU Gao sheng,R OSEM AN R D.T emperatur e and voltage effects on microstructure and electrical behavio r of donormodified BaT iO 3[J].F er roelectrics,1999,221:181 185.[7] 刘清青.SrF eO 3-x 的高温氧吸附等温线[J].郑州大学学报,2000,32(2):44 46.[8] 黄庆,高廉,曲远方.BaT iO 3基PT C 陶瓷低阻化新途径与显微分析[J].硅酸盐学报,2003,31(8):738 740.Mechanism of PTC EffectMO Wen ling 1, ZHANG Qing jun 2, HU Lin yan 3, SHEN Yi 2(1.College of Information,Hebei Polytechnic University,Hebei T angshan 063009,China;2.College of M aterial s,Hebei Polytechnic University,Hebei Tangshan 063009,China;3.Dali an Institute of Chemical Physics,Ch i nese Academy Sciences,Liaoning Dalian 116023,China)Abstract :The electrical property,interface morphology ,the distribution of ox ygen and dom ain of ce ramic materials w ith different donor doped w ere studied in this paper and the results indicated that ceramic semiconducting w ere very fast and the most important factor to affect ceramic semiconducting career was sinting temperature;ox ygen w as segregated in crystal boundary and this w as important to form barrier;do main structure varied when different elements w ere adulterated;domain and the resistance jumping property w ere related.Key words :PTC effect;crystal interface;BaT iO 3ceram ic;domain (责任编辑 刘新喜)422河北师范大学学报(自然科学版)第30卷。
电气石矿物在陶瓷材料中的应用及作用机理摘要：电气石是一种重要的天然矿物材料，在很多领域有着广泛的应用。
本文首先介绍了电气石的成分，结构。
阐述了电气石在陶瓷材料中的应用以及它的作用机理。
关键词：电气石；陶瓷材料；应用Abstract: Tourmaline is an important natural mineral materials, has been widely applied in many fie ld s. T h is p ap er firs t int ro d uces the to ur ma line co mp o s it io n, str uct ure. The t o u r m a l i n e c e r a m i c m a t e r i a l s a s w e l l a s i t s m e c h a n i s m o f a c t io n. Key words: tourmaline ; Ceramic materials ; application1．电气石近年来的研究发现电气石具有永久的辐射远红外线，释放负离子和生物电等特性。
因此电气石逐渐成为热门的天然矿物功能晶体材料，收到世界各国的普遍重视，在环境保护、人体健康、农业生产等领域都具有非常重要的应用价值。
1.1电气石的化学成分电气石Tourmaline ，俗称 碧玺，又译为 托玛琳。
硬度介于7~7.5之间，折射率约为1.62~1.64之间，折射率差约在0.020。
电气石是一种硅酸岩矿物，主要成分有镁，铝，铁，硼等10多种对人体有利的微量元素。
电气石最早发现于斯里兰卡，当时被视为与钻石、红宝石一样珍贵的宝石。
人们注意到这种宝石在受热时会带上电荷，这种现象称为热释电效应，故得名电气石。
其化学通式为：[][]()36618343,NaR Al Si O BO OH F ，式中R 代表金属阳离子，当R 为2M g +、2Fe +或(Li + 加3Al +)时，分别构成镁电气石、铁电气石和锂电气石三个端元矿物种。
第35卷第6期无机材料学报Vol. 35No. 6 2020年6月Journal of Inorganic Materials Jun., 2020文章编号: 1000-324X(2020)06-0633-14 DOI: 10.15541/jim20190308无铅块体陶瓷的电卡效应: 现状与挑战喻瑛1, 杜红亮1,2, 杨泽田1, 靳立2, 屈绍波1(1. 空军工程大学基础部, 西安710051; 2. 西安交通大学电子与信息学部, 电子陶瓷与器件教育部重点实验室,西安710049)摘要: 基于电卡效应的固态制冷技术, 具有高效、环境友好、轻量、低成本和易于小型化等优点, 是替代传统压缩机制冷的理想技术之一。
在施加或去除电场时产生较大极化变化的铁电材料, 则是制备基于电卡效应固态制冷器件的理想材料。
近年来, 人类对环境可持续发展的需求, 使无铅块体陶瓷的电卡效应研究成为铁电材料领域的研究热点之一。
本文首先回顾电卡效应研究历史上的标志性事件, 随后简要介绍电卡制冷的原理, 提出了在室温附近获得宽温区和大电卡温变的材料设计思路, 之后系统综述了BaTiO3基、Bi0.5Na0.5TiO3基和K0.5Na0.5NbO3基无铅块体陶瓷电卡效应的研究进展, 重点分析了这三类无铅块体陶瓷电卡效应的独特优势和面临的挑战, 最后对无铅块体陶瓷电卡效应的发展趋势进行了展望。
关键词: 无铅块体陶瓷; 电卡效应; 击穿场强; 相变; 综述中图分类号: TB64文献标识码: AElectrocaloric Effect of Lead-free Bulk Ceramics: Current Status and ChallengesYU Ying1, DU Hongliang1,2, YANG Zetian1, JIN Li2, QU Shaobo1(1. Department of Basic Sciences, Air Force Engineering University, Xi'an 710051, China; 2. Electronic Materials ResearchLaboratory, School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, China)Abstract: Solid-state cooling technology based on the electrocaloric (EC) effect is attracting increasing attention as an important alternative for traditional cooling systems because of its advantages of high efficiency, environmental friendliness, light weight, low cost, and easy miniaturization. Ferroelectric materials are suitable candidates for EC re-frigeration due to their large polarization and entropy change through applying or removing an external electric field.Recently, study on the EC effect of lead-free bulk ceramics has become one of hot topics on ferroelectric community due to the requirements of sustainable development. In this review, we firstly introduce the significant history events in EC research and the basic principles of EC refrigeration. Then, design strategy for achieving a large EC temperature change near room temperature and a wide using range is summarized. Subsequently, we systematically review the re-search status of EC effect in BaTiO3-based, Bi0.5Na0.5TiO3-based and K0.5Na0.5NbO3-based lead-free bulk ceramics and discuss their advantages as well as challenges. Finally, we propose some prospects for the future work on EC effect in lead-free bulk ceramics.Key words: lead-free bulk ceramics; electrocaloric effect; dielectric breakdown strength; phase transition; review 随着人类生活的飞速发展, 能源危机与环境问题日趋严重。
硕士学位论文（1-x）NBT-x ST无铅陶瓷的电卡效应和储能性能ELECTROCALORIC EFFECT AND ENERGY STORAGE PERFORMANCE OF(1-x)NBT-x ST LEAD-FREE CERAMICS戴祥福哈尔滨工业大学2015年6月国内图书分类号：TB331学校代码：10213国际图书分类号：621密级：公开工程硕士学位论文（1-x）NBT-x ST无铅陶瓷的电卡效应和储能性能硕士研究生：戴祥福导师：李伟力教授申请学位：工程硕士学科：材料工程所在单位：材料科学与工程学院答辩日期：2015年6月授予学位单位：哈尔滨工业大学Classified Index:TB331U.D.C:621Dissertation for the Master Degree in EngineeringELECTROCALORIC EFFECT AND ENERGY STORAGE PERFORMANCE OF(1-x)NBT-x STLEAD-FREE CERAMICSCandidate：Dai XiangfuSupervisor：Prof.Li WeiliAcademic Degree Applied for：Master of Engineering Speciality：Materials Engineering Affiliation：School of Materials Science andEngineeringDate of Defence：June,2015Degree-Conferring-Institution：Harbin Institute of Technology哈尔滨工业大学工学硕士学位论文摘要铁电材料的电卡效应制冷具有高效、节能、环保、成本低的优点，且尺寸可变,可以满足不同设备的制冷要求。
目前无铅铁电陶瓷电热制冷存在的问题有：制冷温差多小于1K；工作温度区间较窄；工作温度过高或过低偏离室温。
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氧化环形钛酸锶压敏陶瓷温度氧化环形钛酸锶压敏陶瓷（简称PST）是一种具有压电和热释电双向耦合特性的功能材料。
它由钛酸锶(SrTiO3)和氧化锶(SrO)两种化合物组成，具有优秀的高温稳定性和良好的压电性能。
本文将重点介绍PST陶瓷的温度特性。
PST陶瓷是一种热释电压敏陶瓷，其压电特性与温度密切相关。
一般来说，PST陶瓷的压电系数随着温度的升高而下降。
这是因为随着温度的升高，晶格的热振动会增强，从而减小了晶格的畸变程度。
而晶格的畸变是产生压电效应的基础，因此当温度升高时，PST陶瓷的压电性能会下降。
然而，尽管PST陶瓷的压电性能受到温度的影响，但它仍然具有较好的高温稳定性。
PST陶瓷的居里温度约为380℃，在该温度以下，PST陶瓷的压电特性较为稳定。
这使得PST陶瓷在高温环境下仍然能够发挥压电特性，因此它在高温传感器、高温压力传感器等领域有着广泛的应用前景。
除了压电特性外，PST陶瓷还具有热释电特性。
热释电是指当温度发生变化时，PST陶瓷产生的电荷也会发生变化。
这是由于PST陶瓷的晶格结构发生变化所导致的。
当温度升高时，PST陶瓷的晶格结构会发生扭曲，从而引起电荷的变化。
这种热释电特性使得PST陶瓷在温度传感器、热敏电池等领域有着广泛的应用。
尽管PST陶瓷具有热释电特性，但它的热敏性能较差，即在较低的温度变化下，PST陶瓷产生的电荷变化较小。
因此，为了提高PST陶瓷的热敏性能，可以采用掺杂和微结构调控等方法来改善其热敏性能。
此外，PST陶瓷的温度特性还与其微结构和制备工艺有关。
PST陶瓷的微结构可以通过改变制备工艺来调控。
例如，可以通过改变烧结温度、烧结时间等参数来控制PST陶瓷的晶粒尺寸和晶界分布。
这些微结构的变化会对PST陶瓷的温度特性产生影响。
因此，在制备PST陶瓷时，需要综合考虑其微结构和温度特性之间的关系。
总结一下，PST陶瓷是一种具有压电和热释电双向耦合特性的功能材料。
其压电性能随着温度的升高而下降，但在高温下仍然具有较好的稳定性。
Ba_(1-x)K_xPbO_3系导电陶瓷的电性能研究陆裕东;王歆;庄志强【期刊名称】《稀有金属》【年(卷),期】2005(29)5【摘要】采用Ba(OH)2·8H2O, Pb(CH3COO)2·3H2O和KOH为原料, 柠檬酸和乙二胺四乙酸(EDTA)为复合螯合剂, 采用溶胶凝胶工艺制备了K掺杂BaPbO3(BPO)陶瓷, 讨论了不同的K受主掺杂浓度对BPO导电陶瓷的电导率和阻温特性的影响.实验结果表明: 采用Sol-Gel法获得了均一相、化学计量比的K掺杂BPO陶瓷;K-BPO陶瓷的室温电阻率随K掺杂量呈倒'S'形状变化, 当掺杂量为3%～5%(摩尔分数)时室温电阻率最低, 约为4.5×10-4 Ω·cm;另外, 与BaTiO3系PTC陶瓷不同, PBO陶瓷引入受主杂质K后, 不但可以降低材料的室温电阻率, 而且可以使材料呈现出一定的PTC效应.【总页数】4页(P643-646)【关键词】BaPbO3;导电陶瓷;受主掺杂;电导率;阻温特性;Sol—Gel【作者】陆裕东;王歆;庄志强【作者单位】华南理工大学材料学院【正文语种】中文【中图分类】TQ174【相关文献】1.Ba_(1-x)Sr_xPbO_3系导电陶瓷及其导电性的研究 [J], 肖洪地;王成建;王矜奉2.(Ba_(1-x)Sr_x)(Zn_(1/3)Nb_(2/3))O_3微波介质陶瓷微结构对介电性能的影响[J], 石锋3.(1-x)Ba_(0.998)La_(0.002)TiO_3+xBi_4Ti_3O_(12)陶瓷电性能的研究 [J], 赵新;蒲永平;王瑾菲;陈小龙;杨公安4.(Ba_(1-x)Sr_x)(Mg_(1/3)Ta_(2/3))O_3微波陶瓷介电性能研究 [J], 刘丹丹;吴顺华;王伟5.直接反应烧结法制备(Ba_(1-x)Ca_x)(Ti_(0.85)Zr_(0.15))O_3陶瓷的微观结构和电性能研究 [J], 陈明丽;仇红;李敏;徐志军;初瑞清;马帅;姬万滨;李国荣因版权原因，仅展示原文概要，查看原文内容请购买。
Y2O3-BaTiO3-ZnO陶瓷的制备及其性能的研究
张小飞
【期刊名称】《陶瓷》
【年(卷),期】2018(0)8
【摘要】笔者采用传统的固相反应法,制备了掺入Y2O3的BaTiO3-ZnO陶瓷,通过对所制备陶瓷样品的结构、常温介电、压电、铁电性能的分析发现:①与未掺入Y2O3的BaTiO3-ZnO陶瓷相比,Y2O3的掺入减小了BaTiO3-ZnO陶瓷的径向收缩率、密度和晶胞体积,同时使材料的晶系结构由立方相转变为四方相结构,Y3+进入BaTiO3-ZnO陶瓷晶格中并与之形成了固溶体;②Y2O3的掺入可以提高样品的矫顽场(Ec),但对材料压电系数变化不大,介电常数总体在减小,当未掺入Y2O3时,样品的介电常数最大(e'=257 7),样品的介电损耗最小(tanδ=0.008 3).
【总页数】6页(P31-36)
【作者】张小飞
【作者单位】榆林市新科技开发有限公司陕西榆林718100
【正文语种】中文
【中图分类】TQ174.75
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因版权原因，仅展示原文概要，查看原文内容请购买。
第43卷第6期2015年6月硅酸盐学报Vol. 43，No. 6June，2015 JOURNAL OF THE CHINESE CERAMIC SOCIETY DOI：10.14062/j.issn.0454-5648.2015.06.04热压烧结对锆钛酸铅镧陶瓷电卡效应的影响王顺达，朱定洋，曾亦可(华中科技大学光学与电子信息学院，武汉 430074)摘要：探讨热压烧结工艺对PLZT(锆钛酸铅镧)陶瓷材料介电击穿性能、饱和极化强度以及电卡性能的影响。
通过X射线衍射和扫描电子显微镜，分析陶瓷样品的相组成和微观结构。
结果表明，热压烧结法有助于控制陶瓷晶粒的生长，提高陶瓷的致密度并增大陶瓷的介电击穿场强，从而有效提高陶瓷的电卡性能以及电卡转换效率。
在328K(55 ℃)与478K(205 ℃)附近，分别发生低温铁电三方相到高温铁电三方相的相变(F RL−F RH)以及高温铁电三方相到立方顺电相(F RH−P c)的相变，展现了比较好的弛豫性，在室温下达到3.6K的绝热温变与1.8×0−7 (K·m)/V的电卡转换效率，具有良好的电卡性能。
关键词：铁电陶瓷；锆钛酸铅镧；电卡效应中图分类号：TM282 文献标志码：A 文章编号：0454–5648(2015)06–0728–06网络出版时间：2015–6–3 15:26:37网络出版地址：/kcms/detail/11.2310.TQ.20150603.1526.004.html Influence of Hot-press Sintering on Electrocaloric Effects of Lead Lanthanum ZirconateTitanate CeramicsWANG Shunda, ZHU Dingyang, ZENG Yike(School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China) Abstract: The influence of hot-press sintering on the dielectric breakdown strength, polarization and electrocaloric effects of lead lanthanum zirconate titanate ceramics was investigated. The microstructure and phases of materials were characterized by scanning electron microscopy and X-ray diffraction. Compared to the conventional solid-state sintering method, hot-press sintering process can control the grain growth, and enhance the bulk density of the samples and the dielectric breakdown strength, thus effectively improving the electrocaloric effect and electrocaloric coefficients. At 328K and 478K, the phase transfers from low-temperature ferroelectric rhombohedral to high-temperature ferroelectric rhombohedral and from high-temperature ferroelectric rhombohedral to paraelectric phase, respectively, showing the superior dielectric relaxation properties. At room temperature, the samples fabricated by hot-press sintering method exhibit a good electrocaloric performance, i.e., a large adiabatic temperature drop of 3.6 K and a great electrocaloric coefficient (|ΔT/ΔE|=1.8×10−7 (K·m)/V).Key words: ferroelectric ceramics; lead lanthanum zirconate titanate; electrocaloric effect随着制冷设备在日常生活和医学领域的广泛应用，人们对制冷技术的要求越来越高。
第34卷 第9期 无 机 材 料 学 报Vol. 34No. 9 2019年9月Journal of Inorganic MaterialsSep., 2019Received date: 2018-11-20; Modified date: 2019-01-30Foundation item: National Natural Science Foundation of China (11604354, 11774366); Chinese Academy of Sciences President’sInternational Fellowship initiative (2017VEA0002); Research Equipment Program of Chinese Academy of Sciences (YJKYYQ20170018)Biography: HAN Liu-Yang (1991-), female, candidate of PhD. E-mail: hanliuyang@ Article ID: 1000-324X(2019)09-1011-04 DOI: 10.15541/jim20180551Electrocaloric Effect in Pb 0.3Ca x Sr 0.7-x TiO 3 Ceramics Near Room TemperatureHAN Liu-Yang 1,2,3, GUO Shao-Bo 1, YAN Shi-Guang 1, RÉMIENS Denis 3, WANG Gen-Shui 1, DONG Xian-Lin 1(1. Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sci-ences, Shanghai 200050, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China; 3. Université Poly-technique Hauts-de-France, Valenciennes 59313, France)Abstract: The electrocaloric (EC) effect is strongly related to interaction of polarization and temperature changes,showing great potential in high-efficient solid state refrigeration. This work focuses on the Pb 0.3Ca x Sr 0.7–x TiO 3 (PCST(x ), x = 0.00, 0.05, 0.10, 0.15) ceramics in which the influence of Ca content on dielectric and ferroelectric property under electric field was studied, and the EC temperature change was calculated through indirect method. Sub-stitution of Ca largely modifies the diffused phase transition behaviors of PCST ceramics, which the diffusion expo-nent of PCST(0.05) increases with electric field up, indicating a promising wide temperature range of large electro-caloric effect. Thus, the largest adiabatic temperature change (1.71 K) is obtained near the room temperature in PCST(0.05) by indirect method. With an electric field of 8 kV/mm, PCST(0.05) ceramic shows good EC effect in a wide temperature range that the adiabatic temperature change is larger than 1 K from 5 ℃ to 70 ℃.Key words: electrocaloric effect; ferroelectrics ceramics; diffused phase transition When an electric field is applied or removed, there is a reversible temperature change in dielectric materials that can be exploited as promising solid-state refrigeration candidates to replace vapor-compression systems [1-3]. In 2006, the giant EC response with an adiabatic tempera-ture change (ΔT ) of 12 K was demonstrated in Pb(Zr 0.95Ti 0.05)O 3 (PZT) antiferroelectric films near the Curie temperature (T C ) for a huge polarization change [4]. From then on, a booming development of EC effect started, and many advancements have been achieved [3,5-7].The pyroelectric and EC effects of ferroelectrics are strongly correlated with each other. The EC effect is the thermodynamically reverse process of pyroelectric effect due to Maxwell relationship. Thus many pyroelectrics can also be good EC materials for solid-state refrigera-tion, such as PZT, Ba x Sr 1–x TiO 3 (BST) and PbSc 1/2Ta 1/2O 3 (PScT)[5, 8-11]. Much attention has been especially paid on BST and PScT for its large pyroelectric effect near the room temperature [5, 8, 10-11]. Recently, Pb 0.3Ca x Sr 0.7–x TiO 3 [PCST(x ), x = 0.00, 0.05, 0.10, 0.15] was reported to show high pyroelectric coefficient near room temperature [12], and the maximum of pyroelectric coefficient is obtained under a very low electric field of 200 V/mm. The diffused phase transitions occur in PCST(x ) ceramics, which maylead to a wide EC temperature span. The enhanced py-roelectric properties and the low induced-electric-field of PCST(x ) ceramics predict high EC effect in PCST(x ) ceramics, indicating great potential in electrocaloric solid-state refrigeration devices.This work focuses on the EC effect of Pb 0.3Ca x Sr 0.7–x TiO 3 (PCST(x ), x =0.00, 0.05, 0.10, 0.15) ceramics. The PCST(x ) ceramics experience typical diffused phase transition, thus good EC effects were observed in a wide tempera-ture span. The optimized EC effect was obtained in 0.05 Ca-doped ceramic, and the indirect EC method was car-ried out to verify ΔT values.1 ExperimentalThe Pb 0.3Ca x Sr 0.7–x TiO 3 (x = 0.00, 0.05, 0.10 and 0.15) ceramics were fabricated by conventional solid-state re-action. The raw materials, Pb 3O 4 (99.26%), SrCO 3 (99%), TiO 2 (99.38%), and CaCO 3 (99%) with 0.5wt% excess of Pb 3O 4 to compensate for Pb volatilization, were well mixed by sufficient ball-milling. Then the mixed raw materials were calcined at 900 ℃ for 2 h. The calcined PCST(x ) powders were shaped into φ15 mm green com-pact and sintered at 1280 ℃ for 2 h. The temperature1012无 机 材 料 学 报 第34卷dependence of dielectric constant was measured by a Hewlett Packard LCR meter at 1 kHz during heating (2 K/min). The polarization versus electric field (P-E ) hysteresis loops from 5 ℃ to 90 ℃ were measured with aixACCT TF Analyzer 2000 at 1 Hz. The densities of the samples were measured using the Archimedes method. The specific heat used in this work is approximated from the specific heat value of PST from Ref.[6, 13-14]. In the EC effect calculation, six fold polynomial fitting wasused to calculated the EP T ∂⎛⎫⎪∂⎝⎭.2 Results and Discussion2.1 Dielectric propertiesThe temperature dependence of dielectric permittivityfor PCST(x ) ceramics is given in Fig. 1(a). The ferroelectric- paraelectric phase transition of PCST(x ) ceramics hap-pens near the room temperature. The electric field is be-lieved to stabilize the ferroelectric phase when the tem-perature is higher than T C . Thus the peak value of dielec-tric permittivity is suppressed with an electric field of 0.5 kV/mm. To reveal it clearly, the diffusion exponent of the phase transition can be characterized by [8] Eq(1):2max max ()112C r T T γεεεσ--= (1) where max εand T C are the peak value of dielectric constantFig. 1 (a) Temperature dependence of dielectric permittivity for PCST(x ) ceramics with and without electric field, and (b) diffu-sion exponent versus electric field curves of PCST(x ) ceramics and the corresponding temperature, γ the diffusion expo-nent, and σ the variance. The diffusion exponent of sam-ples with electric field were given in Fig. 1(b). As it was reported, the phase transition of PCST(x ≤0.10) is second- order transition, while the phase transition order is first order in PCST(0.15)[12]. In general, γ increases with elec-tric field when a second order phase transition occurred (x ≤0.10). For x =0.15, where the first order phase transi-tion happened, γ firstly decreases then increases with electric field up. The diffusion exponent of PCST(0.05) rises from 1.36 to 1.68 with an electric field changing from 0 to 0.5 kV/mm, indicating an enhanced diffused transition happened with electric field increasing. These diffusion behaviors under electric field give us expecta-tion for a temperature-broadened EC effect in PCST(x ) ceramics with application of large electric field [13-14].2.2 Ferroelectric propertiesFig. 2 shows the P-E loops of PCST(x ) ceramics at 5 ℃, and inset shows the composition-dependent T C in PCST(x ) ceramics. The samples show the similar slim ferroelectric hysteresis loops with small coercive field. The maximums of the polarization (P max ) of samples are different and peak at x =0.05.2.3 Electrocaloric propertiesFig. 3(a) shows the P-E loops of PCST(0.05) ceramic with an electric field of 8 kV/mm at different tempera-tures, and the inset illustrates the temperature depend-ence of the polarization under different electric fields. It is seen that the polarization decreases sharply just above T C under low electric fields but decreases slowly under high electric field. Based on the Maxwell relationship [15], the adiabatic temperature change (ΔT ) of EC effect can be calculated by,21d E E ET P T E c T ρ∂⎛⎫∆=-⎪∂⎝⎭⎰ (2)Where ρ is the density and c is the specific heat (426 J/(kg·K)).Fig. 2 P-E loops of PCST(x ) ceramics at 5 ℃ with inset showing the composition dependence of Curie temperature in PCST(x ) ceramics第9期HAN Liu-Yang, et al: Electrocaloric Effect in Pb0.3Ca x Sr0.7-x TiO3 Ceramics Near Room Temperature 1013Fig. 3 (a) P-E loops under different temperatures, and (b) calculated ΔT-T curves under different electric fields of PCST(0.05) sampleThe temperature dependence of the ΔT for PCST(0.05) under different electric fields is given in Fig. 3(b). The maximum ΔT is obtained at the temperature slightly higher than T C and increases gradually with the increase of the electric field.The indirect ΔT as a function of temperature in PCST(x) ceramics is shown in Fig. 4. The maximum of ΔT reaches 1.71 K under an electric field of 8 kV/mm in PCST(0.05) ceramic at 22 ℃, and the diffused phase transition con-tributes to a wide temperature range, where the ΔT of PCST (0.05) ceramic is higher than 1 K even at 70 ℃. The span from 5 to 70 ℃is the main operating temperature range for many devices, as well for cooling applications.Fig. 4 Calculated ΔT-T curves of PCST(x) ceramics In Table 1, the EC properties of PCST(x) are listed, and other EC materials that show good EC effect are given for comparison. Since the practical cooling devices work at room temperature to a large extent, PCST(0.05) ceramic exhibits good performance at room temperature compared to other EC materials. Meanwhile, the ΔT of PCST(0.05) ceramic larger than 1 K from 5 ℃to 70 ℃. All these superior performances demonstrate that PCST (0.05) is a good EC material with high cooling efficiency.3 ConclusionsIn summary, the dielectric diffusion behaviors of PCST(x) ceramics under electric field were systematically studied, all samples show the increasing diffusion exponent with high electric field applied. When Ca substitution is 0.05, the sample shows the largest P max. The enhanced EC effect near the room temperature with the broadened range is obtained by the indirect method based on the Maxwell relationship. The EC response of PCST(0.05) reaches 1.71 K at 20 ℃, and it is larger than 1 K in a wide tem-perature range from 5 ℃to 70 ℃. Therefore the EC effect near the room temperature with the wide range ex-hibits great potential for practical cooling applications.Table 1 Comparison of EC properties of common reported materials Material Form T C/℃ΔT/KΔE/(kV⋅mm-1)(ΔT/ΔE)/(×10-6, K⋅m⋅V-1)Method Ref.PCST(0.00) Ceramic 14.9 1.52 8.0 0.19 Indirect This work PCST(0.05) Ceramic 19.5 1.71 8.0 0.21 Indirect This work PCST(0.10) Ceramic 18.0 1.43 8.0 0.18 Indirect This work PCST(0.15) Ceramic 8.0 1.49 8.0 0.19 Indirect This work PbZr0.95Ti0.05O3Film 226.0 12.00 77.6 0.15 Indirect [4] PbMg1/3Nb2/3O3Ceramic 67.0 2.50 9.0 0.27 Direct [16] 0.75PMN-0.25PT Single crystal 110.0 0.66 2.5 0.26 Direct [17]PMN-30PT Ceramic 145.0 2.60 9.0 0.29 Direct [16] Ba0.94Dy0.04TiO3Ceramic 138.0 1.04 3.0 0.35 Direct [18] BaZr0.2Ti0.8O3Ceramic 39.0 4.50 14.5 0.31 Direct [19] BaTiO3Single crystal 129.0 0.90 1.2 0.75 Direct [7]1014 无机材料学报第34卷References:[1] MOYA X, KAR-NARAYAN S, MATHUR N D. Caloric materialsnear ferroic phase transitions. 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Journal of Materials Chemistry C, 2016, 4: 1842–1849.[19] QIAN X, YE H, ZHANG Y, et al.Giant electrocaloric responseover a broad temperature range in modified BaTiO3 ceramics. Ad-vanced Functional Materials, 2014, 24(9): 1300–1305.Pb0.3Ca x Sr0.7 x TiO3陶瓷的室温电卡效应韩刘洋1,2,3, 郭少波1, 闫世光1, RÉMIENS Denis3, 王根水1, 董显林1 (1. 中国科学院上海硅酸盐研究所，无机功能与器件重点实验室，上海200050；2. 中国科学院大学，北京100049；3. 上法兰西理工大学, 瓦朗谢纳59313, 法国)摘要: 电卡效应是极性材料中极化强度和温度的相互作用, 具有电卡效应的铁电陶瓷材料在高效固态制冷领域有很好的应用前景。
