Effects of Yttrium Doping on the Grain and Grain‐Boundary Resistivities of BaTiO3for Positive Temperature Coefficient Thermistors
作者:
Philippe Blanchart,
Jean François Baumard,
Pierre Abelard,
期刊:
Journal of the American Ceramic Society
(WILEY Available online 1992)
卷期:
Volume 75,
issue 5
页码: 1068-1072
ISSN:0002-7820
年代: 1992
DOI:10.1111/j.1151-2916.1992.tb05539.x
出版商: Blackwell Publishing Ltd
关键词: thermistors;positive temperature coefficient of resistivity;barium titanate;impedance;spectroscopy
数据来源: WILEY
摘要:
Several positive temperature coefficient (PTC) thermistors made of barium titanate with an excess of titania and containing additives such as yttria, and eventually silica, have been prepared following two different routes. The electrical properties of the ceramic samples have been studied at room temperature, i.e., below the transition temperature, using complex impedance spectroscopy. The latter proved to be very useful to measure separately the grain and grain‐boundary resistivities which have been followed as a function of the yttrium concentration. They behave very similarly and go through a minimum for the same composition. From both electrical resistivity measurements and local chemical analysis, it is inferred that the average dopant concentration in the grains is lower than the nominal content in the starting powders. An overall interpretation is given, emphasizing the importance of liquid‐phase sinter
点击下载:
PDF
(466KB)
返 回