A novel route for processing cobalt-chromium-molybdenum orthopaedic alloys.

Spark plasma sintering has been used for the first time to prepare the ASTM F75 cobalt-chromium-molybdenum (Co-Cr-Mo) orthopaedic alloy composition using nanopowders. In the preliminary work presented in this report, the effect of processing variables on the structural features of the alloy (phases present, grain size and microstructure) has been investigated. Specimens of greater than 99.5 per cent theoretical density were obtained. Carbide phases were not detected in the microstructure but oxides were present. However, harder materials with finer grains were produced, compared with the commonly used cast/wrought processing methods, probably because of the presence of oxides in the microstructure.