钛酸钡陶瓷晶界结构、偏析与性能

Grain-Boundary Structure,Segregation and Properties of Barium Titanate Ceramics

本文根据国内外近年来BaTiO3 陶瓷晶界结构及晶界偏析的研究成果 ,总结了BaTiO3 陶瓷中存在的晶界偏析现象 ,分析了产生晶界偏析的主要因素 ,以及晶界偏析对BaTiO3 陶瓷电性能的影响 ;指出了BaTiO3 陶瓷晶界结构与晶界偏析研究中还存在的问题及今后的发展趋势。目前的研究结果表明 :Ba TiO3 陶瓷中存在大量孪晶界 ;晶界偏析相当普遍 ,晶界电势与弹性应变能是偏析的主要驱动力 ,动力学条件也是引起晶界偏析的重要因素 ;偏析对BaTiO3 陶瓷的电性能有很大的影响 ,偏析使得晶界结构和组成不同于晶粒内部 ,在晶界上形成一个n -i-n结构的晶界高阻层 ,这正是PTCR和IBLC的基础。

This paper reviews the last studied-results concerning the grain-boundary structure and segregation of barium titanate ceramics in recent years,summaries the segregating phenomenon in BaTiO 3 ceramics,emphatically analyzes the important factors of resulting in grain-boundary segregation and influence of segregation on the electrical properties of doped polycrystalline BaTiO 3, points out the existential problems and the developing tendencies in respect of researches on GB structure and GB segregation of BaTiO 3 ceramics.To date,the results of researches show that there are masses of twin grain-boundary in BaTiO 3 ceramics, segregating phemomenon is very common, the space-charge potential and elastic strain energy are the major driving forces for segregating,to calculate room-temperature compositions in the interfacial region,kinetic factors must be considered.GB segregation causes the GB structure and composition difference from that of the bulk,the structure at the grain-boundary approximates a n-i-n mode, this just is the basis of PTCR and IBLC.