Crystallization and microstructure development of Si2N4-Ti(C, N)-Y2O3 ceramics derived from chemically modified perhydropolysilazane

[Si-Y-Ti-O-C-N] multicomponent amorphous powders were synthesized by pyrolysis at 1000 degreesC, in NH3 flow, of chemically modified perhydropolysilazane using Y(OCH(CH3)(2))(3) and Ti(N(CH3)(2))(4). The [Si-Y-Ti-O-C-N] powders were fully crystallized to yield Ti(C, N) nano/micro particle-dispersed beta -Si3N4Y2O3 ceramics by hot pressing at 1800 degreesC in N-2. The resulting ceramics exhibited a uniform and fine-grained microstructure. Titanium in the [Si-Y-Ti-O-C-N] powders could act as a catalyst to accelerate alpha-/beta Si3N4 phase transformation as well as an in-situ source for nano/micro Ti(C, N) particles, which lead to microstructural uniformity and grain refinement of beta -Si3N4-Ti(C, N)-Y2O3 ceramics.