Abstract
A novel (Ba,Bi,Nb)-doped TiO 2 ceramic was previously proved to be potentially useful as a varistor material. The present work attempts to clarify the roles of the dopants, Ba and Bi. Varied atmosphere compensation is an effective method to achieve the goal. The results show that varied atmosphere compensation had only a little influence on grain growth and microstructures in the interior of the sintered samples, whereas the varistor properties were affected greatly. Samples compensating with Ba are more beneficial to the boundary barrier than samples compensating with Bi only. Furthermore, samples compensating with both Ba and Bi are better than those compensating with Ba only. This is induced by different degrees of Bi evaporation and Ba diffusion from sintered compacts when sintering proceeds at high temperature.