| 摘要 |
A composite contact material for light-duty electrical contacts is formed by combining, typically by powder-metallurgical techniques, a matrix metal and particles of a conductive material that is typically harder and more corrosion resistant than the matrix metal, and by removing, in a differential material removal step, some of the matrix metal from a surface of the composite, thereby producing a "sandpaper" surface with a substantial number of the particles projecting by a substantial amount above the matrix metal surface. Typical matrix metals are copper, copper alloys, or nickel, and typical particle materials are metals such as Ru, Re, Os, and intermetallics, oxides, borides, nitrides, carbides, silicides, and phosphides of such metals as Al, Ti, Ni, Nb, Mo, Ru, Ta, W, Re, or Os. Particle size is typically between about 0.1 mu m and 100 mu m, preferably less than 10 mu m, and the particle volume fraction is typically between about 1% and 50%, preferably between 5% and 30%. Any appropriate differential material removal method, including chemical, plasma, sputter, thermal, and electrolytic etching, can be used.
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