Nanomechanical and Wear Behavior of Microtextured Carbide Coated CoCrMo Alloy Surfaces

Abstract

The nanomechanical properties of a CoCrMo medical implant alloy and a novel microtextured carbidecoated CoCrMo alloy (MTCC) surface—hardness and elastic modulus—were examined using nanoindentation. The MTCC surfaces may be a successful alternative bearing material for artificial joints. Understanding the nanomechanical, material properties, and surface morphology of the MTCC–CoCrMo surface are important for designing wear resistant artificial joints. The microtextured carbide surfaces were created using a microwave plasmaassisted chemical vapor deposition reaction (MPCVD). Nanomechanical 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 h) in static environments and under severe wear conditions. The hardness, elastic modulus, and surface parameters of the 4h MTCC surfaces were always greater than the 2h MTCC and CoCrMo alloy surfaces. The nanomechanical properties changed for the CoCrMo alloy and 2h and 4h MTCC surfaces after, in contrast to before, wear testing. This indicates that the wear mechanisms affect the nanomechanical results. Overall, the 4h MTCC surfaces had greater wear resistance than the 2h MTCC or CoCrMo alloy surfaces.