【摘要】 用显微观察分析、I-V特性及复阻抗频谱的测量,研究了不同Nb5+和Sr2+掺量的SrO-Nb2O5-TiO2系半导体压敏陶瓷材料的微观结构和相关电学性质;讨论了掺杂Nb5+和Sr2+的分布和作用;Nb5+固溶在TiO2中取代Ti4+并使晶粒成为半导化,同时也有助于晶粒生长;而 Sr2+主要分布在晶粒边界处,对表面受主态及材料相关电学性能有重要影响;在大气气氛中热处理后的实验结果表明:处理温度在800℃以上时,能显著提高压敏电压,但只有适当的热处理温度。才能使非线性系数有所改善.更多还原

【Abstract】 By microstructure analysis, I - V characteristics and complex impedance spectra measurement, the microstructure and related electric properties for the varistors based on SrO-Nb2O5-TiO2 semiconducting ceramics with different doped amounts of Nb5+ and Sr2+ were investigated. The distribution and effects of Nb5+ and Sr2+ on electric properties for the materials were discussed. The results show that Nb5+ dissolves into TiO2 grains substitutes Ti4+ to enhance ceramic semiconducting behavior, and proper addition of Nb-doped amount can avail grain growing. The Sr2+ mainly distributes in grain boundary areas, which behaves as an interface acceptor state and so influences on the electric properties of varistor markedly. The experimental results on post heat-treatment in air show that the varistor voltage is increased observably with heat-treatment temperature above 800℃, but the nonlinear coefficient is ameliorated only at an appropriate temperature range.更多还原