Masatada Yodogawa

Ceramic Manufacturing Technology for the High Performance PTC Thermistor

The roles and the effects of transition elements and other additives on the resistivity and the ratio of the resistivity rise of the semiconducting barium titanate ceramics are presented. The variety of the typical experimental data are illustrated to explain that the exact controlling up to ppm order of the small amount components including both impurities and additives as well as the controlling of the characteristics attributing to the powder, is very important technology for the industrial manufacturing of the high performance positive temperature coefficient (PTC) thermistor. The importance of the exact controlling of the whole firing program is also discussed, indicating the existence of particular temperature ranges at high temperature regions, both in the heating and cooling processes.