Tribological behavior of high-density polyethylene in dry sliding contact with ion-implanted CoCrMo

摘要

The surface of a CoCrMo alloy has been modified using beamline ion implantation of boron, carbon and nitrogen, and diamond-like carbon (DLC) deposition. All surface treatments, with the exception of high-dose nitrogen-ion implantation, result inan increase in surface hardness. However, wear and friction either remain similar to, or become worse than, those of the unimplanted alloy. Experiments show that adhesion energy and energy of deformation are the two major components influencing thefrictional behavior of the CoCrMo-high-density polyethylene (HDPE) wear system. Wear was dominated by material loss in the HDPE pin. No correlation between wear and CoCrMo hardness was observed, indicating that adhesion or plowing in HDPE pins is notcorrelated with the mechanical properties of the counterface materials. A comparison of the ion-implanted samples with DLC-coated CoCrMo showed the HDPE-DLC sliding system to have the largest coefficient of friction. The friction behavior of this systemwas found to be controlled by an adhesive build-up of HDPE on the DLC surface.