(Ta, Cr)-doped TiO2 electroceramic systems

A study was made to identify how the addition of Ta and Cr oxides influences the electronic properties of the TiO2 varistor, aiming to obtain low voltage varistors. The results of an electric characterization, allied with a microstructural analysis, clarify and confirm the influence of these dopants on the varistors properties of these systems. This study, in which Cr2O3 is used as dopant, clearly shows that the action of these dopants in the creation of electronic barriers is more efficient when these oxides are associated with Ta2O5, and that an breakdown electric field of 40 V/cm and a nonlinear coefficient of 12 can be obtained after heat treatment in an oxygen-rich atmosphere. (C) 2006 Springer Science + Business Media, Inc.