Effect of Pr6O11 doping on the microstructure and electrical properties of ZnO varistors
Effect of Pr6O11 doping on the microstructure and electrical properties of ZnO varistors
复制标题
Pr6O11掺杂对ZnO压敏电阻微观结构和电性能的影响
DOI：
10.1016/j.ceramint.2019.08.219
复制
发表时间：
2019-12-15
影响因子：
5.2
通讯作者：
Liu, Jianke
中科院分区：
文献类型：
--
作者：
Cao, Wenbin;Xie, Xin;Liu, Jianke
ZnO-Pr_6 O_（11）压敏电阻在电力系统中具有良好的应用前景，但对其微观结构的研究还很薄弱。本文详细研究了Pr_6 O_（11）掺杂对传统固相烧结法制备的ZnO-Pr_6 O_（11）-Co_2O_3-Cr_2O_3-Y_2O_3压敏电阻器的微观结构（如元素分布和晶界特征）和电学性能的影响。未掺杂Pr 6 O 11时，元素在ZnO相内部和晶界的分布相似，不能形成双肖特基势垒。Pr 6 O 11掺杂时，烧结过程中形成Pr 6 O 11液相，溶解了大量的Zn、Cr和Y，冷却过程中在ZnO晶界形成Pr 6 O 11固相，形成双肖特基势垒。Pr_6 O_（11）掺杂量为0.25 ~ 1mol%时，样品的电压梯度E ~（-1）mA和非线性系数α均明显大于未掺杂的样品，且随着Pr_6 O_（11）掺杂量从0增加到1mol%，α和E ~（-1）（mA）均增大。α和E-1（mA）的值同时取决于双肖特基势垒高度phi（B）和CPE指数α（CPE）。最后，在Pr 6 O 11掺杂量为1mol%时，得到了电压梯度为333.6V/mm，非线性系数为24.4的ZnO压敏电阻。深入研究其微观结构及机理对制备具有优良电性能的ZnO-Pr 6 O 11压敏电阻具有重要意义。
ZnO-Pr6O11 based varistors have anticipated application prospect in electrical system, but the study of the detailed microstructure is still poor. In this paper, the effect of Pr6O11 doping on the microstructure (such as element distributions and grain boundary characteristics) and electrical properties of the ZnO-Pr6O11-Co2O3-Cr2O3-Y2O3 varistors manufactured by the conventional solid-state sintering procedure was studied detailedly. Without Pr6O11 doping, the elements have the similar distributions in the interior and grain boundaries of ZnO phase, and the double Schottky barrier cannot be formed. With Pr6O11 doping, Pr6O11 liquid phase dissolving a large number of Zn, Cr, and Y forms during sintering and Pr6O11 solid phase forms in the ZnO grain boundaries during cooling, so the double Schottky barriers form. The voltage gradients E-1 mA and nonlinearity coefficients alpha of the samples with Pr6O11 contents of 0.25-1 mol% are much larger than those of the sample without Pr6O11 doping, and the values of alpha and E-1 (mA) increase with Pr6O11 content increasing from 0 to 1 mol%. The values of alpha and E-1 (mA), simultaneously depend on the double Schottky barrier height phi(b) and the CPE exponent alpha(CPE). Finally, the ZnO varistor with a voltage gradient of 333.6 V/mm and a nonlinearity coefficient of 24.4 was obtained by Pr6O11 doping of 1 mol%. The detailed study of the microstructure and related mechanism is of great importance for preparing ZnO-Pr6O11 based varistors with excellent electrical properties.