NTC THERMISTOR PORCELAIN, PROCESS FOR PRODUCING NTC THERMISTOR PORCELAIN, AND NTC THERMISTOR

摘要

Disclosed is an NTC thermistor porcelain. Also disclosed are a process for producing the NTC thermistor porcelain and an NTC thermistor. The NTC thermistor porcelain comprises a porcelain body (1) formed of a ceramic material of (Mn, Ni)3O4 type or (Mn, Co)3O4 type. The ceramic material constituting the porcelain body (1) has a first phase (2) having a spinel structure and a second phase (3) of a plate crystal having a high electric resistance. The second phase (3) is present in a dispersed state in the first phase (2). The surface of the porcelain body (1) has a heat application path (4) with a predetermined pattern formed by applying heat generated by laser beam irradiation. In the heat application path (4), the second phase (3) disappears and has been integrated in terms of crystal structure with the first phase (2). The plate crystal in the second phase (3) is precipitated in a temperature region of 800°C or below in a temperature falling process in a firing step. The formation of the heat application path (4) facilitates the regulation of the electric resistance value of the NTC thermistor. The above constitution can realize an NTC thermistor porcelain that can easily regulate the electric resistance to a low value even after sintering.