Preparation of Y-SiAlON rod-like crystals and whiskers by combustion synthesis

By combustion synthesis, Y (α + β)-SiAlON ceramic powders consisting of rod-like crystals were prepared. Effect of starting composition on the phase assemblage of combustion products was studied. It was found that with the increase of oxygen content, the phase assemblage of products varied from single-phase α-SiAlON to β-SiAlON gradually. Novel β-SiAlON whiskers were also observed in the combustion products. From the whisker morphology, it was suggested that both VLS and VS mechanisms operated here. It was also noticed that the whiskers could nucleate either on the basal face or on the side faces of as-existed prismatic rod-like crystals.