Effects of plasma nitriding on mechanical and tribological properties of CoCrMo alloy

Surface treatments of orthopedic materials are commonly used to enhance mechanical and tribological properties. One of the well-known orthopedic materials, wrought CoCrMo alloy was nitrided at various temperatures and time periods at a gas mixture of 75%N-2-25%Ar to achieve these enhancements. SEM, XRD, pin-on-disc tribotester, and microhardness tester have been used to examine the treated materials. Analyses confirm the formation of nitride layers and the significant effect of plasma nitriding on wear rate and surface hardness. (C) 2007 Elsevier B.V. All rights reserved.