Synthesis of alumina–silicon carbide composites by chemically activated self-propagating reactions

The synthesis of alumina/silicon carbide composites by self-propagating reactions activated by Teflon is investigated. It is shown that small amounts of this material (i.e. 0.20–0.25 wt.%) guarantee the occurrence of self-propagation reactions leading to the formation of a composite. In particular, under argon atmosphere, it consists of well-formed crystals of alumina, fine grained silicon carbide and whiskers-shaped crystallites of SiC. On the other hand, aluminium nitride, silicon carbonitride/silicon cyanide, aluminum oxynitrisilicides and mullite are also found under nitrogen atmosphere. The content of SiC whiskers in the final product increases when powdered polymers (polystyrene, polyethylene, polypropylene) are added to the initial mixture together with Teflon.