A composite microstructure, consisting of β-sialon, O-sialon and X-sialon phases, was produced by coating β-Si3N4 particles with amorphous alumina followed by hot pressing and reactive sintering at 1923 K. The microstructure, chemistry of the phases and interphase interfaces of this ceramic were characterized by TEM and high resolution AEM. Both polyhedral and elongated β-sialon grains were observed. TEM examination showed the formation of a large number of β-sialon grains and PEELS and EDS X-ray microanalysts in AEM revealed they had varing amounts of aluminum and oxygen contents. HREM examination of several interphase interfaces and triple junctions suggests that the amount of glassy phase in the produced ceramic is substantially lower compared to those reported in the literature. This is of importance for high temperature properties.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry