Effect of MnO2 addition on microstructure and electrical properties of ZnO–V2O5-based varistor ceramics

Abstract The microstructure and electrical properties of ternary system ZnO–0.5 mol% V 2 O 5 –MnO 2 ceramics sintered were investigated in accordance with MnO 2 content by sintering at 900 °C. For all samples, the microstructure of the ternary system ZnO–V 2 O 5 –MnO 2 ceramics consisted of mainly ZnO grain and secondary phase Zn 3 (VO 4 ) 2 . The incorporation of MnO 2 to the binary system ZnO–V 2 O 5 ceramics was found to restrict the abnormal grain growth of ZnO. The breakdown field in the E – J characteristics increased from 175 to 992 V/cm with the increase of MnO 2 content. The incorporation of MnO 2 improved non-ohmic properties by increasing non-ohmic coefficient. The highest non-ohmic coefficient (27.2) in the ternary system ZnO–0.5 mol% V 2 O 5 –MnO 2 was obtained for MnO 2 content of 2.0 mol%.