Inhibition grain growth and electrical properties by adding In2O3 to SnO2-Co3O4-Ta2O5 ceramics

Mauricio Olvera, Marla Berenice Hernández Hernández, Sergio Garcia Villarreal, Eden Amaral Rodríguez Castellanos, Cristian Gomez, Linda Garcia, Josue Amilcar Aguilar Martinez

Abstract


In this contribution the effect of In2O3 additions on the microstructure, physical, and electrical properties of the SnO2-Co3O4-Ta2O5 ceramic system was investigated. Since 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 (a) and breakdown voltage (EB), 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 () 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.

 

 


Keywords


Electrical properties, Varistors, Sintering, Grain boundaries, Breakdown voltage.

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DOI: https://doi.org/10.31349/RevMexFis.65.25

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Revista Mexicana de Física

ISSN: 0035-001X

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