Characterization and fabrication of Y-SiAlON ceramics

Keywords: Si3N4, Y2O3, ?SiAlON, Sintering SiAlON ceramics is one of the most important engineering metarials which have wide range of application areas. It can be produced with various phase compositions and different production methods. In this study, two different starting compositions were prepared according to two cation values, and then the mixture was compacted uniaxially in a die and the green compacts were subjected to cold isostatic pressing. The green compacts were sintered at 1700 ?C and 1750 ?C for 30 and 120 min under nitrogen atmosphere. The sintered compacts were analysed for hardness, densification phase and microstructre investigation. The results showed that the starting composition was suitable for manufabrication of Y- SiAlON ceramics. X-Ray difraction analysis showed that ?-SiAlON phase was dominat phases in the sintered compacts. The densification of the compacts are related with sintering temperatures and sintering times. For the densification of the Y-SiAlON compacts(1700?C) and shorter sintering duration are suitable. Weight loss in the compacts, were seen dure to the vaporization of nitrogen and oxygen from the nitrides and oxides structures at higher sintering temperature and holding time Addition of alumina was increased, the hardness and densification of the compacts. It was also accelerated the formation of liquid phase in the compacts.