Synthesis of Pr6O11 and Y2O3 Doped Zinc Varistors by High Energy Milling

High voltage zinc varistors were synthesized by high-energy milling with Pr6O11 and Y2O3 doped ZnO-Bi2O3 system as raw materials. The effects of high-energy milling on the microstructures, electrical properties and densities of samples were investigated in detail. The results show that high-energy milling make the as-prepared varistors have refined and homogeneous microstructures, which result in improving their electrical properties. The optimal prepared samples were obtained by milling for 7.5 hours and sintering at 1100 degrees C, which exhibited varistor voltage (V-1mA) of about 533 V/mm, non linear coefficient (alpha) reaching 36 and leakage current (I-L) of 2.96 mu A.