Synthesis, Characterization of Perhydropolysilazane and Its Application in the Preparation of 3D SiO_(2f)/Si_3N_4 composites

摘要

Perhydropolysilazane was synthesized by the ammonolysis of dichlorosilane-pyridine adduct, and used as precursor to prepare three-dimensional silica fiber reinforced silicon nitride matrix composites via preceramic polymer infiltration and pyrolysis at 1073K in anhydrous ammonia atmosphere. The polymer-derived ceramic matrix was amorphous near-stoichiometric silicon nitride with an empirical formula of SiN_(1.34)O_(0.02)C_(0.01)H_(1.21). The as-received composites were amorphous with a high density of 1.96g/cm~3 after five infiltration-pyrolysis cycles. The process was successful to fabricate dense silicon nitride matrix composites reinforced by three-dimensional silica fiber due to the low viscosity, good wettability and high ceramic yield of Perhydropolysilazane.