Resumen

OLVERA-SANCHEZ, M. et al. Inhibition grain growth and electrical properties by adding In₂O₃ to SnO₂-Co₃O₄-Ta₂O₅ ceramics. Rev. mex. fis. [online]. 2019, vol.65, n.1, pp.25-30.  Epub 09-Nov-2019. ISSN 0035-001X.

In this contribution, the effect of In2O3 additions on the microstructure, physical and electrical properties of the SnO2-Co3O4-Ta2O5 ceramic system was investigated. Because the effect of In2O3 has been studied typically at low levels, special attention has been paid to the effect of high levels (1 and 2 mol % In2O3) in the ceramics. Results show that up to 0.1 mol % In2O3, an increase of indium oxide content is correlated with grain size reduction and an increase of the nonlinearity coefficient (α) and breakdown voltage (E B ), producing an augmentation by a factor of 2 in the nonlinearity coefficient and an increment by a factor of 8 in the breakdown voltage. However, shrinkage (γ) and measured density are not influenced by the addition of indium oxide. For samples with 1 and 2 mol % In2O3, in non-calcined condition, In2O3 is present with cubic structure. However, in calcined specimens, In2O3 is not detected anymore and SnO2-crystal structure undergoes a change from tetragonal to cubic. These ceramic samples exhibit high resistivity, behaving like dielectric materials.

Palabras llave : Electrical properties; varistors; sintering; grain boundaries; breakdown voltage; 81.20.Ev; 61.05.cp; 84.32.Ff.

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