Influence of sintering on microstructure and electrical properties of ZnO-based multilayer varistor (MLV)

The effect of sintering on microstructure, dielectric property and varistor property of ZnO-based multilayer varistor (MLV) were investigated. The results show that an optimum microstructure of ZnO-based MLV can be obtained when sintering at 950 degrees C/1.5 h. The reaction between ZnO and Sb2O3 is noted. Also, the segregation of Bi2O3 to the inner electrode and thus the reaction of Bi2O3 with Pd are observed. The VB and ce value of ZnO-based MLV can be controlled in a straightforward manner through the control of grain size. The decrease in VB directly relates to the grain growth of ZnO grains when increasing the sintering temperatures from 900 to 1050 degrees C. Moreover, the increase of capacitance with sintering temperature may mainly result from the coalescence of ZnO matrix grains. The energy absorption capabilities in terms of electro-static discharge (ESD) and peak current (PC) measurements of ZnO-based MLV are reported. The optimum varistor properties of ZnO-based MLV can be obtained when sintering at 950 degrees C. (C) 2006 Elsevier Ltd and Techna Group S.r.l. All rights reserved.