PTC热敏电阻陶瓷材料线性化机理与实验研究

LINEARIZATION MECHANISM AND EXPERIMENTALINVESTIGATION OF PTC CERAMIC MATERIALS FORTHERMISTOR APPLICATION

从施主掺杂BaTiO_3陶瓷的晶界双肖特基势垒模型出发,作者分析了在晶界受主态密度相当小的情况下,以自由电子的漂移和扩散为主的传导过程的晶界等效电阻与温度的关系式,并进行了数值拟合.

An analysis based on the double Shottcky barriers model at the grain boundaries of donor dopant BaTiO3 oeramios indicated that the drift and diffusion conducting mechanism of free electrons might be substituted by a simple thermal excitation mechanism in the case of low density acceptor states at the grain boundaries; the relationship of equivalent resistivity dependence on temperature was derived and fitted with values; the results showed that the resistivity of PTC oeramic materials in the paraelectric phase was linear over a rather wide range of temperature.The results of experimental investigation on PTC oeramio materials based on (Ba-Sr)TiO3 showed that the density of the acceptor states at grain boundaries could be controlled by the modifier of composition and process, and the PTC ceramic materials with excellent linearity in the temperature region of about 120°C could be prepared. The experimental results were also discussed.