METHOD OF IMPROVING THE THERMO-MECHANICAL PROPERTIES OF FIBER-REINFORCED SILICON CARBIDE MATRIX COMPOSITES

摘要

A thermal treatment process for improving thermo-mechanical properties of ceramic matrix composite materials such as silicon carbide (SiC) matrix composites is described. The treatment process removes excess silicon and/or other process-related defects from the SiC-based matrix as well as the fiber interfacial coating. This invention can be practiced with minimal strength loss for as-fabricated composites formed from high-strength continuous-length ceramic and carbon-based fibers that are functionally stable to 1600° C. and above. The invention provides a method for significantly improving composite thermal conductivity and creep resistance, and for reducing composite porosity. It has been demonstrated using state-of-the-art 2D woven SiC/SiC composites containing Sylramic-iBN SiC fibers, boron-nitride-based interfacial coatings, and hybrid matrices that are based on SIC formed by chemical vapor infiltration (CVI) and by a combination of CNI, SiC particulate infiltration, polymer infiltration and pyrolysis, and melt infiltration of silicon, silicon-based alloys, and silicides.