Reversible α⇌ sialon transformation in heat-treated sialon ceramics

H. Mandal, D. P. Thompson*, T. Ekström

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

150 Citations (Scopus)

Abstract

Typical β-sialon and mixed α-β-sialon starting compositions have been densified by pressureless sintering using either Ln2O3 or equimolar mixtures of Ln2O3 + Y2O3 where Ln = Sm, Dy, Yb. The resulting materials were heat treated at 1000-1500°C to devitrify the grain boundary glass into crystalline oxynitride phases. The effects of rare earth ionic size and heat-treatment temperature on the stability of devitrified phases, microstructure and mechanical properties have been studied. Microstructural characterisation of the α-sialon phase formed in these systems revealed that α is only stable at high temperatures and transforms to β-sialon plus grain boundary phases at lower temperatures; this provides an excellent mechanism for controlling the mechanical properties of the final material.

Original languageEnglish
Pages (from-to)421-429
Number of pages9
JournalJournal of the European Ceramic Society
Volume12
Issue number6
DOIs
Publication statusPublished - 1993
Externally publishedYes

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