LI Zhihui, HOU Tiecui, LU Hongxia, ZHANG Rui

(College of Materials Science and Engineering, Zhenzhou Univers ity, 450002)

Abstract: 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 characteris tics 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 res is tivity, the res is tance    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 resis tivity 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.

Keywords: PTC ceramics , donor doping, acceptor doping, R- T characteristics