Effect of Cr(2)0(3) on the microstructure and non-ohmic properties of (Co, Sb)-doped SnO2 varistors
The effect of Cr2O3 addition on the physical characteristics, microstructure, and current-voltage properties of (Co-Sb)-doped SnO2 varistors was investigated. SnO2-Co3O4-Sb2O5 ceramics with additions of 0.0, 0.03, 0.05 and 0.07 mol % Cr2O3 were sintered at 1350 ºC under ambient atmosphere and characterized microstructurally and electrically. The characterization by XRD and SEM show that the microstructure remains as a single phase material with multimodal size distribution of SnO2 grains. The greatest effect of Cr2O3additions is manifested in the electric breakdown field. Additions of high levels (0.07 and 0.05 %) of this oxide promote an increase of approximately 55% in this parameter compared to the Cr2O3-free sample. Another physical property is affected: the measured density values decreases as the Cr2O3 content increases. A change in the nonlinearity coefficient value is produced only at the highest Cr2O3 content while at intermediate levels there is not change at all. Consequently, when seeking high nonlinearity coefficients, intermediate levels of Cr2O3 are not recommended.
| Main Authors: | , , , , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Sociedad Mexicana de Física
2013
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| Online Access: | http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0035-001X2013000100003 |
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