Synthesis, Characterization of Perhydropolysilazane and its Application in the Preparation of 3D SiO2f/Si 3N4 Composites

Abstract

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 1073Kin anhydrous ammonia atmosphere. The polymer-derived ceramic matrix was amorphous near-stoichiometric silicon nitride with an empirical formula of SiN1.34O0.02C0.01H1.21. The as-received composites were amorphous with a high density of 1.96g/cm3 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.