QUANTITATIVE MICROSTRUCTURAL ANALYSIS OF REACTION-BONDED SILICON-NITRIDE

Quantitative analysis of the essential microstructural parameters of injection-moulded reaction-bonded silicon nitride was performed. The effect of silicon grain size on the porosity, the pore size distribution, the degree of reaction and the proportions of the alpha and beta modifications and the grain size of these phases was studied under constant processing conditions. With increasing silicon grain size the degree of reaction and the total porosity and density remain unaffected. The percentage of beta phase, the grain size of alpha and beta modifications as well as the mean pore diameter increase with increasing grain size of the starting powders. The effect of the structural parameters on the room-temperature strength is discussed. © 1979 Chapman and Hall Ltd.