Metal-on-metal wear testing of Co-Cr alloys

The wear characteristics of various Co-Cr alloy combinations were studied using a reciprocating wear machine. Wear test specimens were made from three Co-Cr alloys, cast Co-Cr, low carbon wrought Co-Cr and high carbon wrought Co-Cr alloys. The cast Co-Cr alloy was evaluated in both the as-cast and the solution-treated conditions. All specimens were polished with a surface roughness in the range of 0.01-0.02 mu m The clearance in diameter between the convex and the concave specimens was 100 or 300 mu m. The same test conditions were applied to all specimens. Results showed that the best alloy couple was as-cast Co-Cr on as-cast Co-Cr alloy and this couple was found to be superior to the high carbon wrought on the high carbon wrought couple. This finding is also supported by using a hip simulator wear test machine.