Fe_2O_3掺杂对ZnO-Pr_6O_(11)系压敏电阻材料电学性能的影响

通过烧结法制备了Fe2O3掺杂的ZnO–Pr6O11压敏电阻材料,研究了Fe2O3掺杂量对ZnO–Pr6O11系压敏电阻材料电学性能的影响。实验表明:当Fe2O3掺杂量小于0.005%(摩尔分数,下同)时,ZnO–Pr6O11系压敏电阻材料的非线性系数和压敏电压随Fe2O3掺杂量增大而逐渐提高。当Fe2O3掺杂量为0.005%时,压敏电压达到最大值571V/mm,非线性系数达到最大值26。当Fe2O3掺杂量大于0.005%时,非线性系数和压敏电压均急剧下降。过量Fe2O3使ZnO压敏电阻材料非线性下降的主要原因是:Fe元素偏析在晶界处,提供额外载流子降低了晶界电阻率,同时晶界处PrFeO3相的堆积会破坏晶界结构,从而影响压敏电阻材料的电学性能。

INFLUENCE OF Fe_2O_3 DOPING ON THE ELECTRICAL PROPERTIES OF ZnO-Pr6O11BASED VARISTOR MATERIALS

ZnO-Pr6O11 based varistor materials doped with Fe2O3 were prepared by sintering process,and the influence of Fe2O3 doping on the electrical properties of ZnO-Pr6O11 based varistor materials was investigated. The results show that when the doping amount of Fe2O3 is less than 0.005% in mole （the same below）,the nonlinear coefficient and the varistor voltage of ZnO-Pr6O11-based varistor materials increase with the increase of Fe2O3 doping amount. When the doping amount of Fe2O3 is 0.005%,the varistor voltage and the nonlinear coefficient reach the maximum value of 571 V/mm and 26,respectively. However,when the doping amount of Fe2O3 is more than 0.005%,the nonlinear coefficient and varistor voltage of the proposed materials dramatically decrease. Excessive doping of Fe2O3 makes the nonlinear property of ZnO based varistor material degrade,because more Fe atoms would exist at the grain boundaries,providing more carriers that decrease the resistance of the grain boundaries,and PrFeO3 would be formed,destroying the construction of the grain boundary.