Degradation of oxide varistor ceramics in air atmosphere containing NO2 at elevated temperatures

Alexander Glot, Elisabetta Di Bartolomeo, Aleksei Gaponov, Riccardo Polini*, Enrico Traversa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The heat treatment of commercial zinc oxide based varistor ceramics at temperatures of 200-300 °C in air with 1000 ppm of NO2 causes strong shift of voltage-current characteristic (VCC) to low voltages. Subsequent exposure to pure air leads to partial restoration of VCC. Scanning electron microscopy analysis showed microstructural changes of samples after heat treatment in air with 1000 ppm of NO2. Chemical reactions between NO2 molecules and oxygen chemisorbed or Bi-rich oxide phases at grain boundaries followed by the lowering of grain boundary potential barriers can be the reason of observed degradation.

Original languageEnglish (US)
Pages (from-to)1213-1216
Number of pages4
JournalJournal of the European Ceramic Society
Volume24
Issue number6
DOIs
StatePublished - Jan 1 2004

Keywords

  • Grain boundary
  • NO
  • Sensors
  • Varistors
  • ZnO

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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