稀土Pr_6O_(11)掺杂水平对ZnO-Pr_6O_(11)-Co_3O_4-TiO_2压敏电阻材料的微观结构和电学性能的影响

Effect of Pr_6O_(11) Doping on the Microstructural and Electrical Properties of ZnO-Pr_6O_(11)-Co_3O_4-TiO_2 Ceramic Varistors

通过传统陶瓷工艺,在1350℃下烧结得到了不同稀土Pr6O11掺杂水平的ZnO-Pr6O11-Co3O4-TiO2压敏电阻材料,研究了Pr6O11掺杂水平对压敏电阻材料微观结构和电学性能的影响。结果表明:随着Pr6O11掺杂水平的变化,样品相组成没有发生变化,样品由ZnO、Pr6O11、Zn2TiO4和PrTiO34种相组成;Pr6O11掺杂既能促进样品烧结致密,还可抑制ZnO晶粒的生长;在Pr6O11掺杂量不超过2.0mol%时,Pr6O11掺杂水平提高可提高样品压敏电压,在Pr6O11掺杂量不超过1.5mol%时,Pr6O11掺杂水平提高可提高样品非线性系数,降低漏电流。

ZnO-Pr6O11-Co3O4 -TiO2 ceramic varistors with different doping levels of Pr6O11 were prepared at 1350 ℃ by a conventional processing method. The effect of Pr6O11 doping on the microstructure and electrical properties of the as-prepared ZnO-Pr6O11 -based ceramic varistors was investigated. X-ray diffraction analysis indicates that the change in the designed doping level of Pr6O11 has no obvious influence on the phase composition of the varistor ceramics; they are all composed of ZnO, Pr6O11 , Zn2TiO4 and PrTiO3 phases. Scanning electron microscopy observation reveals that the doping of Pr6O11 can promote the sintering of the samples, and inhibits the growth of ZnO grains. The measurement on electrical field vs current density indicates that when the doping level of Pr6O11 is no more than 2.0 mol%, with increasing doping amount of Pr6O11 , the varistor voltage of the samples increases; when the doping level of Pr6O11 is no more than 1.5 mol%, with increasing doping amount of Pr6O11 , the nonlinear coefficient of the varistors increases and the leakage current decreases.