Y_2O_3掺杂ZnO-Bi_2O_3压敏瓷的显微组织和电性能

Microstructure and Electrical Properties of Y_2O_3-doped ZnO-Bi_2O_3-based Varistor Ceramics

为了提高氧化锌压敏瓷的综合电性能,采用高能球磨制备Y2O3掺杂ZnO压敏瓷,通过扫描电镜和X射线衍射对其显微组织和相成分进行了分析,探讨了Y2O3对氧化锌压敏瓷电性能和显微组织影响机理。结果表明,Y2O3掺杂摩尔分数在0～1.00%时,压敏瓷的电位梯度为332～597V/mm,非线性系数为23.6～40.1,漏电流为0.06～0.90μA。当Y2O3掺杂摩尔分数为0.60%时氧化锌压敏瓷的综合电性能最好,压敏瓷电位梯度为482V/mm,非线性系数为35,漏电流为0.17μA。掺杂Y2O3使压敏瓷晶粒细化是由于Y2O3或者单独以Y2O3氧化物形式存在,钉扎在晶界,阻碍晶粒长大;或者与Bi2O3固溶形成含Y的富铋相,使Bi2O3促进晶粒生长的作用受到抑制。

Y2O3-doped ZnO-Bi2O3-based varistor ceramics were prepared by using high energy ball milling, and the electrical properties and microstructure of the varistor ceramics were studied. With addition of 0- 1.00% Y2）O , Y2O3-doped ZnO-based varistor ceramics were prepared with the voltage gradient of 332- 597 V/mm, the nonlinear coefficient of 23.6-40.1, and the leakage current of 0.06-0.90 μA. The results show with addition of 0. 600% Y2O3, Y2O3-doped ZnO-based varistor ceramics exhibit comparatively ideal comprehensive electrical properties, such as the threshold voltage is 482 V/mm, the nonlinear coefficient is 34.8 and the leakage current is 0.17 μA. As Y2 O3 content increases, the grain size decreases. Existence of some Y2 O3 at the grain boundaries hinders the movement of the grain boundaries, and some Y2O3 dissolves in Bi2O3 liquid to form the intergranular Bi-rich phase content with Y, thus, Bi2O3 hinders the grain growth.