FANG Zhiyuan , SHEN Chunying , QIU Tai

(College of Materials Science and Engineering, Nanjing University of Technology, Nanjing Jiangsu 210009, China)

Abstract: This paper studies the effect of the CaTiO₃ content and the sinter temperature on the properties and microstructure of (Ba,Pb)TiO₃-based PTC materials. The results show that the optimium addition level of CaTiO₃ is 3mol% with the minimum room temperature resistivity and the best PTC effect. SEM observation shows that the grain is more uniform and compact after the addition of CaTiO₃ . The results show that the higher the sinter temperature is, the higher the temperature coefficient is. The heat preservation of the cooling phase can enhance the PTC effect.

Key words: calcium titanate; barium titanate; PTC thermistors; ceramics