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 language | English |
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Pages (from-to) | 421-429 |
Number of pages | 9 |
Journal | Journal of the European Ceramic Society |
Volume | 12 |
Issue number | 6 |
DOIs | |
Publication status | Published - 1993 |
Externally published | Yes |