Influence of Ta2O5 doping and microwave sintering on TiO2-based varistor properties

TiO2 based varistor materials with Ta2O5 dopants are prepared by microwave sintering (MS) and conventional sintering (CS). The sintering characteristics, sintered microstructures, varistor voltage (V1 mA), nonlinear coefficient (α) and leak current (IL) are studied. The influences of the doping amount of Ta2O5 on the above properties are discussed. For similar sintered densities, the microwave sintering can decrease the sintering temperature by about 250 °Cwhile improving the microstructure of the samples. Microwave sintering leads to better properties than conventional sintering. The samples have the best overall properties when the doping amount of Ta2O5 is in the range from 0.075 mol% to 0.125 mol%.