Defect profile and microstructural development in SnO 2-based varistors

The microstructural development and the stabilised valence of the ions added to SnO 2 were analysed. Aiming at a better interpretation of the involved phenomena, the effects on grain growth, secondary phase formation and structure of adding Co 3O 4, ZnO, MnO 2, Sb 2O 3, or Nb 2O 5 have been studied....

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Bibliographic Details
Published inJournal of the European Ceramic Society Vol. 23; no. 10; pp. 1585 - 1591
Main Authors Fayat, J., Castro, M.S.
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 2003
Subjects
Defects
Grain growth
Microstructure-final
SnO 2
Varistors
Varistors
Microstructure-final
SnO 2
Grain growth
Defects
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Summary:The microstructural development and the stabilised valence of the ions added to SnO 2 were analysed. Aiming at a better interpretation of the involved phenomena, the effects on grain growth, secondary phase formation and structure of adding Co 3O 4, ZnO, MnO 2, Sb 2O 3, or Nb 2O 5 have been studied. We found that cobalt, zinc and manganese stabilise as Co +2, Zn +2 and Mn +2 in the lattice, favouring the oxygen vacancy apparition and then, the grain growth and the potential barrier formation. Sb 2O 3 or Nb 2O 5 reduces the total oxygen vacancy concentration and the grain growth. Sb 2O 3 addition favours the CoSnO 3 particle formation and Nb 2O 5 favours the formation of particles with an intermediate composition between CoSnO 3 and Co 2SnO 4 in systems with Co 3O 4. These particles could also control the sintering and grain growth rates.
ISSN:0955-2219
1873-619X
DOI:10.1016/S0955-2219(02)00405-3