Si3N4-TiN-Y2O3 ceramics derived from chemically modified perhydropolysilazane

[Si-Y-Ti-O-C-N] multicomponent powders were synthesized by pyrolysis at 1000 degrees C, in NH3 flow, of chemically modified perhydropolysilazane using 4 yttrium triisopropoxide and titanium tetrachloride. [Si-Y-Ti-O-C-N] powders yielded uniform and fine-grained Si3N4-TiN-Y2O3 ceramics by heat treatment at 1800 degrees C in N-2. The fully densified Si3N4-TiN-Y2O3 ceramics were also synthesized by heat treatment at 1800 degrees C, followed by powder-vehicle hot pressing at 1800 degrees C in N-2. The resulting ceramics revealed that TN was dispersed as particles having a size range of about 60-600 nm and the fine particles less than 80 nm were dispersed within the beta-Si3N4 matrix grains.