Corrosion Behavior of Alumina Ceramics in Caustic Alkaline Solutions at High Temperatures

Tsugio Sato, Shigeki Sato, Akitsugu Okuwaki, Syun‐ichiro ‐i Tanaka

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

The corrosion rate and changes in the microstructure and fracture strength of alumina ceramics (93.0% Al2O3 and 99.5% Al2O3) were studied in 0.1m to 25m NaOH solutions at 150°C to 200°C, where m= mol/(kg of H2O). The attack of the caustic alkaline solution started at the grain boundaries. Consequently, the corrosion resistance increased with decreasing SiO2 content in Al2O3 ceramics, and the corrosion resistance of 99.5% pure Al2O3 was similar to that of Si3N4 ceramics. Since large pits are formed by corrosion, the surface area increased first and the apparent corrosion rate increased with time in the initial stage of the corrosion. The corrosion rate of Al2O3 increased linearly with increasing NaOH concentration, and the activation energy was 102 kJ/mol. The fracture strength of corroded Al2O3 decreased monotonically as the degree of dissolution of alumina increased.

Original languageEnglish
Pages (from-to)3081-3084
Number of pages4
JournalJournal of the American Ceramic Society
Volume74
Issue number12
DOIs
Publication statusPublished - 1991 Dec

Keywords

  • alkali resistance
  • alumina
  • corrosion resistance
  • grain boundaries
  • silica

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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