Abstract:
Novel mixed rare earth Sc
2O
3 and Y
2O
3 doped ZnO-Bi
2O
3 based varistor ceramics were prepared by a solid reaction route, their electrical properties and microstructure were studied. The results show that mixed rare earth doping can improve the comprehensive performance of ZnO-Bi
2O
3 based varistor ceramics more remarkably than single rare earth doping, but the effect of mixed rare earth doping on their electrical properties is consistent with that of single rare earth doping. When the content of Sc
2O
3 is the same, the voltage gradient of mixed rare earth Sc
2O
3 and Y
2O
3 doped ZnO-Bi
2O
3 based varistor ceramics increases with the increase of the amount of Y
2O
3; when the content of Y
2O
3 is the same, the nonlinear coefficient of the varistor ceramics increases with the increase of the amount of Se
2O
3. After adding 0.12% Sc
2O
3 and 0.20% Y
2O
3 (molar fraction), mixed rare earth Sc
2O
3 and Y
2O
3 doped ZnO-Bi
2O
3 based varistor ceramics exhibit comparatively ideal comprehensive electrical properties:the threshold voltage is 410 V·mm
-1 the nonlinear coefficient is 38.0, and the leakage current is 0.58 μA.