两种晶型的TiO_2粉体对PTCR温度系数的影响

Influences of Crystal Structure of TiO_2 Powders on the Temperature Coefficient of PTCR Materials

BaTiO3系PTCR元件是近年来发展迅速的一种电子器件,高质量的PTCR原料粉体在一定程度上决定了器件的性能.研究并分析了金红石、锐钛矿两种晶型结构的特性差异,同时讨论了BaTiO3基介电材料相变扩张与其相应PTCR材料温度系数αT间的关系.通过对比得出两种晶型的TiO2粉体对Ba TiO3系PTCR温度系数的影响,并指出在900～1100℃对TiO2粉体进行高温处理完成锐钛矿向金红石的晶型转变后,有利于获得高温度系数的PTCR样品.

The series of BaTiO3's PTCR is one of the fast developing electronic devices. High property raw materials determine the capacity of the devices to some extent.The different characteristic of rutile and anatase is investigated in this paper. The relationship between the diffuse phase transition and the temperature coefficient of resistance of BaTiO3 materials is discussed. It shows that the different crystalline structure can have influence on the temperature coefficient of PTCR, and when heated at 900～1100℃, the anatase TiO2 powders may be converted into the rutile powders. This result may be helpful to obtain PTCR with a higher temperature coefficient.