摘要
钛酸钡陶瓷中，高温下晶格失氧使晶粒内部氧匮乏。在氧化气氛中烧成，晶界则是富氧环境。缺陷或杂 质在晶界上进一步氧化，产生晶粒中并不存在的缺陷种类。杂质和缺陷在晶界上与晶粒内部有不同的行为。某些在 晶界上被氧化成高价态的缺陷和杂质，在晶粒中不能存在，而在晶界上以亚稳态形式存在。它们在铁电相变点跃迁 回低价稳态，产生电子陷阱，使材料电阻率迅速增大，形成ＰＴＣＲ效应。
In BaTiO3 based ceramics sintered in oxidizing atmosphere, oxygen is rich at grain boundary, but is lack in inner grain for the release of oxygen at the high temperature. Defects and impurities may oxidize to higher valence in grain boundary and generate new ones which can not exist in grain bulk. They will get to lower valence which is more stabe during ferroelectric phase transition, and produce electronic trap. These traps enhance materials' resistivity rapidly, and cause the PTCR effects.
出处
《压电与声光》
CSCD
北大核心
2000年第2期114-117,共4页
Piezoelectrics & Acoustooptics
