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Nonlinear electrical properties of cobalt doped SnO2·Ni2O3·Nb2O5 varistors
Published online by Cambridge University Press: 15 October 2001
Abstract
A new varistor system of SnO2·Ni2O3·Nb2O5 exhibits the relative dissatisfactory physical and electrical
properties. The effect of cobalt oxide on the properties of the SnO2·Ni2O3·Nb2O5 varistors was investigated
by measuring the densities, permittivities, the current-voltage properties and the properties of the defect
barriers. It is found that the sample doped with 0.25 mol% Co2O3 exhibits the abnormal poorer electrical
properties than the samples without Co2O3 dopants. However, the sample doped with
6.0 mol% Co2O3
exhibits the highest nonlinear coefficient ($\alpha=17.24$) and reference electrical field ($E_{\rm B}=561$
V/mm),
although the sample doped with 1.0 mol% Co2O3 exhibits the highest densities
($\rho =6.87$
g/cm3) and
permittivities. The sample with 6.0 mol% Co2O3 bears the highest barriers, but the sample with 1.0 mol% Co2O3 shows the narrowest barriers. The investigation of the sintering temperature shows that the samples
sintered at 1450 °C exhibit the better physical and electrical properties. The results were discussed and the
defect barrier model was also introduced to explain.
- Type
- Research Article
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- Copyright
- © EDP Sciences, 2001
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