Comparison of oxidation behaviour of sintered ceramics produced from various silicon nitride powders

Sintered ceramics produced from two kinds of silicon nitride powder were oxidized at 1000 and 1400°C. The density, the mechanical properties and the phase composition of the oxide layer and the internal region (without the oxide scale) of one material were compared with those of the other. It was found that the difference in the starting powder properties caused differences in the oxide layer thickness, and the phase composition and the mechanical properties of the internal part.