Performance evaluation of doped titanium oxide for low-voltage applications

Abstract

Varistors are the electronic devices which are used in various industries to protect the electrical and electronic systems from sudden surges. In this research, the electrical properties of titanium dioxide (TiO2) doped with tantalum pentoxide (Ta2O5), tungsten trioxide (WO3), cobalt oxide (Co3O4), and bismuth oxide (Bi2O3) and fired at different temperatures were investigated for low-voltage applications. The adequate amount of dopants at suitable sintering temperature had beneficial effect in improving the properties of TiO2. The relative density was found to be more than 97% of theoretical density when samples sintered between 1300°C and 1400°C for all composition compared to undoped samples. On the other hand, the addition of dopants enhanced hardness and compressive strength of varistor disks. The average grain size was also increased with the dopants system, making it suitable for low-voltage application. Furthermore, the current-voltage characteristic of the TiO2 revealed a significantly high value of nonlinearity of 19.6. A high dielectric constant of 104 with minimum dissipation factor of 0.002852 at 1 kHz was also obtained, thereby making it suitable for low-voltage application. © 2015 The American Ceramic Society.