PTCR Characteristics of BaTiO3-Based Porous Ceramics Newly Developed by Addition of Partially Oxidized Ti Powder

초록

We have found that (Ba,Sr)TiO3 ceramics sintered in vacuum develops PTCR (positive temperature coefficient of resistivity) characteristics by adding partially oxidized Ti, i.e., TiO2(Ti). Furthermore, we have found that the sintering densification of the compact and the grain growth of (Ba,Sr)TiO3 both hardly occur, resulting in porous and small-grained microstructure. In this report, the results on the effects of some parameters such as the amount of TiO2(Ti), the sintering temperature and time, and the baking temperature on PTCR characteristics, which have separately been reported in the past, were summarized, including new results on the electrical potential barrier and resistivity characteristics of the grain boundary of (Ba,Sr)TiO3.