Investigating the Physical and Mechanical Properties of TiO2 Varistor Materials Prepared with Various Dopants

Abstract

Varistors are the most efficient devices for the protection of power transmission lines and electronic devices against excessive transient surges. The current trends that require varistors with more functions have led to research to develop new ceramic varistor material and titanium dioxide (TiO2) is the emerging new material. In this research nanosized TiO2 was taken as the base materials to which a small amount of impurities was added as dopants for enhancing the properties. Ta2O5, WO3, Bi2O3 and Co3O4 were used as dopants where the percentage of Bi2O3 and Co3O4 was fixed; 0.5% and 0.2% respectively. Samples were prepared with different weight percentages of dopants and sintered at a constant temperature of 1300˚C with 2 hour’s holding time to observe the effect of these dopants on physical and mechanical properties of nanosized TiO2. Analysis was undertaken to evaluate the properties of the nanosized TiO2, such as green density, fired density, fired strength, axial and radial shrinkage. It was found that with the composition of 98.1% TiO2+0.7% Ta2O5+0.5% WO3+0.2%Co3O4+0.5%Bi2O3 have a significant influence on the physical and mechanical properties, which is anticipated to improve the performance of varistor. With the improvement in the physical and mechanical properties of TiO2, the composite material has potential application in low voltage application devices.