Processing of silicon carbide ceramics using chemically modified polycarbosilanes

Chemically modified polycarbosilane (PC) which contains Si-Al-C-O component , PCOAl, was synthesized using PC and aluminum triisopropoxide. Ceramic yie ld was greatly improved through the modification of PC with a metal alkoxid e, The phase transformation behavior and microstructure development of sili con carbide (SiC) were studied on beta-SIC powders coated with chemically m odified PC. The beta-alpha phase transformation of SiC was enhanced by the coating of chemically modified PC on beta-SiC powder. A unique microstructu re with submicron-sized plate-like grains was developed, since the fine alp ha phase produced at low temperature served as a nucleation site for the be ta-alpha phase transformation of SiC.