Guo-Zhong Zang

Effect of SiO2 on the Varistor and Dielectric Properties of SnO2-Zn2SnO4 Ceramic Composites

ABSTRACT SnO2-Zn2SnO4 ceramic composites are prepared by traditional ceramics processing and the effect of SiO2 on the varistor, dielectric properties has been investigated. With increasing SiO2 content to 0.2 mol%, the nonlinear coefficient α and the breakdown electrical field E1.0 gets to the maximum of 7.7 and minimum of 12V.mm–1, respectively. Meanwhile, the dielectric spectra show that the sample doped with 0.2 mol% SiO2 has the highest relative permittivity εr of ∼7×103 at 40 Hz, 40°C. The dielectric temperature spectra show that the temperature stability of the dielectric properties can be improved by doping 0.2 mol% SiO2. The good properties indicate that SiO2 doped SnO2-Zn2SnO4 ceramic composites are viable candidate for capacitor-varistor functional devices to protect electrical micro-machines. Further studies show that the density and grain uniformity of the composites are improved by doping proper content of SiO2. The compact and uniform microstructure may be responsible for the excellent varistor and dielectric properties. GRAPHICAL ABSTRACT