Effect of V2O5 on electrical and microstructural properties of ZnOceramics

Abstract ZnO ceramics with small amounts of V 2 O 5 as a varistor-former ranging from 1–5 mol% were prepared by conventional powder processing route and sintered at 700, 800 and 900 °C for 2 h. It was observed that the grain growth behavior in ZnO ceramics was strongly influenced by doping with V 2 O 5 . Morever, lower temperatures about 900 °C could be used for sintering. The microstructure of the samples consists of ZnO grains as a main phase and Zn 3 (VO 4 ) 2 as a secondary phase. All of the prepared ceramics showed characteristic of non-ohmic current–voltage behavior. Non-linear coefficient increased with increase in V 2 O 5 content and sintering temperature. Activation energy of the ceramics lies in the range of 0.071–0.402 eV which decreased with increase in V 2 O 5 content and sintering temperature. The origin of the non-linear electrical behavior was explained by considering the solid state reactions and formation of the potential barriers at grain boundaries.