Patent ID: 8766145

Claim:
A process for producing a semiconductive porcelain composition provided with an electrode in which the semiconductive porcelain composition is a BaTiO 3 -based semiconductive porcelain composition free of Pb, in which a part of Ba of BaTiO 3 is substituted with Bi—Na, and having a positive temperature coefficient of resistance, the process comprising: a step of preparing a (BaQ)TiO 3 calcined powder (wherein Q is a semiconductor dopant); a step of preparing a (BiNa)TiO 3 calcined powder; a step of mixing the (BaQ)TiO 3 calcined powder and the (BiNa)TiO 3 calcined powder; a step of molding and sintering the mixed calcined powder; a step of heat-treating said obtained sintered body at 600° C. or lower for 1 hour or more in an atmosphere containing oxygen or in the air; and a step of forming the electrode to said obtained sintered body.