The effect of Ta2O5 and Cr2O3 on the electrical properties of TiO2 varistors

An investigation was made of low voltage TiO2 varistors doped with Ta2O5, MnO2 and Cr2O3. Our findings revealed that the addition of 0.25 mol% of Ta2O5 improved the varistors’ characteristics. The addition of Cr2O3 increased the nonlinear coefficient (from 2.6 to 8), thereby producing low voltage varistors (Er=34 V/cm). Thermal treatment in an oxidizing atmosphere improved the nonlinear coefficient and increased the breakdown electric field of the composition under study.