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

The synthesis of alumina/silicon carbide composites by self-propagating rea ctions 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-pro pagation reactions leading to the formation of a composite. In particular, under argon atmosphere, it consists of well-formed crystals of alumina, fin e grained silicon carbide and whiskers-shaped crystallites of SiC. On the o ther hand, aluminium nitride, silicon carbonitride/silicon cyanide, aluminu m oxynitrisilicides and mullite are also found under nitrogen atmosphere. T he content of SIC whiskers in the final product increases when powdered pol ymers (polystyrene, polyethylene, polypropylene) are added to the initial m ixture together with Teflon. (C) 2001 Elsevier Science Ltd and Techna S.r.l . All rights reserved.