Fretting wear studies on PVD TiN coated,ion implanted and thermally oxidised biomedical titanium alloys

Abstract

Fretting damage is normally expected in biomedical implants due to body movements. Titanium alloys are most commonly used for biomedical devices and surface modified alloys have superior tribological properties to virgin materials. In the present study, the fretting wear resistance of physical vapour deposition (PVD) TiN coated, ion implanted and thermally oxidised biomedical alloys have been investigated and compared. PVD TiN coating has shown the best fretting wear resistance with minimum friction coefficient, less wear scar depth and diameter, and minimum wear rate compared to other coatings. The ion implanted specimen has undergone fretting assisted electrochemical dissolution to give higher wear loss after the modified layer has eroded away. Thermal oxidation has shown intermediate response to fretting. Fretting resistance can be improved with layers of high hardness and thickness.