Abstract
Silicon nitride nanocomposites have been investigated with emphasis on the change in microstructure with inclusion of boron nitride or titanium nitride. The fine composite powders of silicon nitride-boron nitride or titanium nitride system were prepared by a vapor phase reaction process and hot-pressed with a sintering aid of yttria-alumina system. Boron nitride tended to be separated from silicon nitride grains during sintering and retard the grain growth. Titanium nitride accelerated the rod-like grain growth of silicon nitride. Silicon nitride-titanium nitride composite was also produced with a sintering aid of yttria-titania-aluminum nitride system in which titanium nitride was formed by the in-situ reaction. In this system also, the rod-like grain growth of silicon nitride was enhanced by inclusion of titanium nitride. The change in microstructure and mechanical properties will be discussed.
