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.
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.
参考文献
| [1] | Cheng Jiannjang, Wu Jennming. Materials Chemistry and Physics, 1997, (48): 129--135. [2] Wu Jennming, Lai Chihhuang. J. Am. Ceramic Soc., 1991, 74 (12): 3112--3117. [3] Yang Senglu, Wu Jennming. J. Am. Ceramic Soc., 1993, 76 (1): 145--152. [4] Yang Senglu, Wu Jennming. J. Mater. Res., 1995, 10 (2): 345--352. [5] Barringer E A, Bowen H K. J. Am. Ceramic Soc., 1982, 65 (2): C199--C201. [6] Yang Senglu, Wu Jennming. J. Am. Ceramic Soc., 1995, 78 (8): 2203--2208. |
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