Artigo
Dependence of the nonlinear electrical behavior of SnO2-based varistors on Cr2O3 addition
Fecha
2007-01-01Registro en:
Ceramics International. Oxford: Elsevier B.V., v. 33, n. 2, p. 187-192, 2007.
0272-8842
10.1016/j.ceramint.2005.07.025
WOS:000244008300010
Autor
Universidade Estadual Paulista (Unesp)
Universidade Federal de São Carlos (UFSCar)
Resumen
Tin dioxide varistors doped with Coo, ZnO, Ta2O5 and Cr2O3 were prepared by the mixed oxide method. Temperature dependent impedance spectroscopy revealed two different activation energies, one at low frequencies and the other at high frequencies. These activation energies were associated with the adsorption and reaction of O-2 species at the grain boundary interface. We show that Cr2O3 improves the varistor properties, generating sites for the adsorption of O' and O at the grain boundary region. The O' and O defects are truly responsible for the barrier formation at the grain boundary interface. (c) 2005 Elsevier Ltd and Techna Group S.r.l. All rights reserved.