Effect of boron nitride on the phase stability and phase transformations in silicon carbide

High-resolution transmission electron microscopy has been used to study the effect of hexagonal boron nitride (h-BN) on the stability of SiC polytypes in Si3N4-particulate-reinforced SIC composites in which h-BN particles appeared as a trace contaminant. In contrast to previous transmission electron microscopy work on SiC-BN composites, our results imply that there is no clear preference for a particular SIC polytype to be stabilized by h-BN nearby, Instead, we propose that previous observations suggesting that the 3C SIC polytype is stabilized by h-BN can be simply explained in terms of it being stabilized indirectly by nitrogen arising from BN dissociation during processing.