高精度高比容独石电容器用瓷料研究及其介电常数的计算  

Study on the Ceramics for MLCC of High Accuracy and Specific Capacity and the Calculation of Its Dielectric Constant

作　　者：肖谧[1] 

机构地区：[1]天津大学电子信息工程学院,天津300072

出　　处：《电子元件与材料》2001年第1期36-37,共2页Electronic Components And Materials

摘　　要：首先利用蒙特卡罗有限元法在分析陶瓷材料内电场分布的基础上 ,对微粒混合陶瓷材料的介电常数与各成分含量及其介电常数之间的关系进行了探讨。研究表明 ,由于介质极化的原因 ,在陶瓷材料内部 ,等势线的分布将主要集中于低介电常数成分所占的区域 ,并且 ,微粒混合陶瓷材料各成分的含量及其介电常数都会对陶瓷材料内电场的分布产生重要影响 ,并使陶瓷材料的宏观介电常数发生变化。当陶瓷材料中含有与其他成分介电常数差别相当大的成分时 ,利用蒙特卡罗有限元法可获得较其他传统方法更为准确的结果系统地研究了钡钛钕系统陶瓷的介电性能。研究结果表明 ,Ba Ti O3中掺入极少量的 Nd2 O3(例如摩尔分数 x为 0 .1% )时 ,材料呈半导性 ,电阻率呈明显的 PTCR效应。Ba Ti O3中掺入少量的 Nd2 O3(x≥ 0 .2 % )时 ,材料呈绝缘性 ,且随着 Nd2 O3掺入量的增加 ,材料的平均晶粒尺寸不断减小 ,居里峰向负温方向移动 ,居里峰不断降低。Ba Ti O3中掺入少量 Nd2 O3· 2 Ti O2时 ,随着掺入量的增加 ,居里峰向负温方向移动 ,晶粒尺寸不断增大 ;Ba Ti O3中掺入较多的 Nd2 O3· 2 Ti O2 时 ,随着掺入量的增加 ,介电常数不断减小 ,介电常数的温度特性曲线的非线性程度不断减小 ,并且 ,当 Ba Ti O3与 Nd2 O3· 2 Ti O2 的摩尔比?Firstly, the relations between dielectric constant of ceramic composed of several compositions and content or dielectric constant of the compositions are studied on the basis of analysis of inner electric field distribution in ceramic using Monte Carlo Finite Element Method in this paper. The results show that, in ceramic, the contour lines of voltage mainly concentrate in the field of composition with low dielectric constant because of the polarization of dielectric. The content and dielectric constant of composition in the ceramic will all affect inner electric field distribution, and thus make the macroscopical dielectric constant of the ceramic different. More accurate results can be gained using Monte Carlo Finite Element Method than other traditional methods when there is a composition which dielectric constant is much different from the other's in ceramic. Dielectric properties of ceramic in barium, titanium and neodymium system are synthetically studied. The results show that, material will be semiconductive, and resistivity shows obviously PTCR effect when little amount of Nd 2O 3 (for example 0 1mol%) doped into BaTiO 3. Material will be insulating when a little amount of Nd 2O 3 (≥0 2mol%) doped into BaTiO 3, and with the increase of doping amount of Nd 2O 3, the average grain size decreases, the Curie point shifts to minus temperature, the Curie summit reduces constantly. When a little amount of Nd 2O 3·2TiO 2 is doped into BaTiO 3, with the increase of doping amount, Curie point shifts to minus temperature, and the average grain size increases constantly. When much Nd 2O 3·2TiO 2 is doped into BaTiO 3, with the increase of doping amount, dielectric constant decreases, nonlinear extent of temperature characteristic curve of dielectric constant reduces, and when the mole ratio of BaTiO 3 and Nd 2O 3·2TiO 2 is equal, the main phase will change from BaTiO 3 to BaNd 2Ti 3O 10 . In barium, titanium and neodymium system, when the ratio of BaO, Nd 2O 3 and TiO 2

关 键 词：高精度 高比容 独石电容器 陶瓷 瓷料 介电常数 

分 类 号：TM28[一般工业技术—材料科学与工程]