Corrosion and strength degradation of Si3N4 and sialons in K2CO3 and K2SO4 melts

T. Sato, Y. Koike, T. Endo, M. Shimada

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    14 Citations (Scopus)

    Abstract

    Si3N4-based ceramics, such as hot isostatically pressed Si3N4, hot-pressed Si3N4, hot-pressed sialons containing 0, 30, 60 and 100% a phase, were corroded by K2SO4 and K2CO3 melts at 1150 to 1300 and 925 to 1150° C, respectively. The surface chemical reaction-controlled shrinking core model adequately described the relationship between the weight loss of the specimen and time for the corrosion reactions in both K2SO4 and K2CO3 melts, and the apparent activation energies were 380 to 608 and 157 to 344 kJ mol-1, respectively. The corrosion rate in K2CO3 melt decreased with increasing content of aluminium and yttrium ions in the specimens, but no systematic relation was observed for the reaction in K2SO4 melts. The fracture strength of the specimens corroded by K2SO4 and K2CO3 melts degraded to 2/3 to 2/5 of the original values up to a 2% weight loss, and then was almost constant up to 30% weight loss.

    Original languageEnglish
    Pages (from-to)1405-1410
    Number of pages6
    JournalJournal of Materials Science
    Volume23
    Issue number4
    DOIs
    Publication statusPublished - 1988 Apr 1

    ASJC Scopus subject areas

    • Materials Science(all)
    • Mechanics of Materials
    • Mechanical Engineering

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