Brief description of the coating of composite materials by strengthened of the fibers and materials thus covered products.

摘要

A coating process for fibre-reinforced ceramic composite materials involves etching the composite material surface to expose fibres which are still intact and bonded to the composite material, prior to applying a coating compsn. Pref. the composite material has a matrix, selected from carbon, silicon carbide, silicon nitride, boron nitride and epoxy and polyimide resins, and fibres, selected from carbon, silicon carbide and aluminoborosilicate. Pref. the surface is etched to a depth of 12.5-255 microns in a reactive gas atmos. pref. comprising Cl2, H2 and HF or H2 and the thermal decompsn. product of a fluorocarbon resin. When the composite material has a high temp. resistant ceramic matrix selected from carbon, boron carbide, silicon carbide and silicon nitride, the atmos. contains H2 and HF. Etching is carried out at 750-1200 deg.C for 0.5-20 hrs. USE/ADVANTAGE - E.g. for aerospace parts such as gas turbine parts, airframe components, rocket engine components, etc. Coating adhesion and exfoliation resistance are much increased and coating performance (oxidn. protection) is improved.