Metal Matrix Composites Applied by Selective Brush Plating

Metal matrix composites were deposited onto the surface of steel and titanium alloys by selective brush plating.  The adhesion of the composites to the substrates was measured using standard tests.  The use of a brush plated nickel interlayer between the substrate and composite coating was found to have a substantial effect on adhesion.  The composites examined include chromium carbide in a cobalt metal matrix also applied by brush plating.  The concentration of carbide in the matrix was varied between 10% and 50% by weight by controlling the deposition conditions.  The particle distribution uniformity throughout the composite was examined by optical cross-section.  The effect of the brush plated Co-Cr₃C₂ composite on the surface properties of wear and high temperature oxidation resistance was measured using Taber wear tests and baking up to 800°C in air.  The stability of the Co-Cr₃C₂ composite was examined through hardness measurement after exposure to a series of temperatures up 800°C.