掺杂对BaTiO_3基PTC陶瓷材料性能的影响

INFLUENCE OF DOPING ON CHARACTERISTICS OF BaTiO_3-BASED PTC CERAMICS

概述了BaTiO3基PTC陶瓷半导化的掺杂种类和机理,综述了掺杂物的添加量和加入方式对BaTiO3基PTC陶瓷材料性能的影响,并展望了其发展趋势。通常BaTiO3陶瓷的电阻率在开始时都随施主掺杂浓度的增加而降低,当施主掺杂浓度达到某一值时,电阻率降至最低,而后随着施主掺杂浓度的提高,电阻率则迅速上升。随着受主掺杂含量的增加,材料的室温电阻率和升阻比逐渐增大,PTC性能逐步提高,当含量超过某一值时,升阻比又呈降低趋势,PTC效应有所降低,室温电阻率依然增大。由于各掺杂物的优缺点不同,近几年研究发现,双施主掺杂和施受主共掺能够很好的改善材料的性能。

This article summarized the kinds and mechanisms of doping used for BaTiO3-based PTC ceramic semiconductors, described the influence of doping quantity and doping style on their characteristics and then explored the prospects of their development. Usually the resistivity of BaTiO3-based PTC ceramics reduces gradually with the density increase of the donor doping until it reaches a const., then it will increase fast. The room-temperature resistivity, the resistance ratio Rmax/Rmin and the PTC effects increase with the density increase of acceptor doping until it reaches a const., then the jump range and the PTC effects will decrease but the room-temperature resistivity will continue to go up. For every dopant has its advantages and disadvantages, results of recent studies show that double-donor doping and donor-acceptor codoping can improve the performance of the material remarkably.