Micro- and Nano-mechanical Properties of a CoCrMo Medical Implant Alloy and the Carbide-CoCrMo Surfaces

The micro- and nano-mechanical properties of a CoCrMo medical implant alloy and a novel micro-textured carbide-coated CoCrMo alloy (MTCC) surface hardness and roughness were examined using micro- and nano-indentation and surface profilometry. The MTCC surfaces may be a successful alternative bearing material for artificial joints. Understanding the micro- and nano-mechanical, material properties and surface morphology of the MTCC-CoCrMo surface are important for designing wear resistant artificial joints. The micro-textured carbide surfaces were created using a microwave plasma assisted chemical vapor deposition reaction (MPCVD). Micro- and nano-mechanical properties, volumetric wear properties, and surface morphology were measured and used to determine the performance of the conventional CoCrMo alloy and MTCC surfaces (processed for either 2 or 4 hours) in static environments and under severe wear conditions. The hardness and surface parameters of the 4h MTCC surfaces were always greater than the 2h MTCC and CoCrMo alloy surfaces. The mirco- and nano-mechanical properties changed for the CoCrMo alloy, 2h, and 4h MTCC surfaces after, in contrast to before, wear testing. This indicates that the wear mechanisms affect the micro- and nano-mechanical results. Overall, the 4h MTCC surfaces had greater wear resistance than the 2h MTCC or CoCrMo alloy surfaces.