SURFACE FINISHES FOR BORON FILAMENTS

Boron filaments were surface finished with inorganic thin films to provide improved adhesion to organic resins and to provide improved high temperature oxidation resistance in boron filament reinforced plastic composites. Surfacing materials included aluminum, titanium, silicon carbide, titanium nitride, titanium diboride, nickel and boron-carbon. These materials, with the exception of boron-carbon were selected because the oxidation products are more resistant to moisture than boron oxides normally occurring on boron filaments. The finishes were applied to the boron filaments by a continuous vapordeposition glow discharge process. Of the finishes examened, those of silicon carbide, silicon and titanium nitride exhibited superior oxidation resistance and greatly improved resin bondability over uncoated boron. (Author)