Diamond-like carbon coatings for orthopaedic applications: an evaluation of tribological performance

A detailed investigation of the tribological behaviour of vacuum are diamon d-like carbon coated Ti-6Al-4V against a medical grade ultra-high molecular weight polyethylene is conducted in this work in order to investigate the potential use of diamond-like carbon coatings for orthopaedic appplications . Lubricated and non-lubricated wear experiments are performed using a stan dard pin-on-disc wear tester. The coefficient of friction is monitored cont inuously during testing and wear rate calculations are performed using surf ace profilometry measurements of worn disc surfaces. Sliding wear tests sho w the existence of two distinct friction and wear regimes distinguished by physically different mechanisms. In the first stages of wear, adhesion and abrasion are the dominant mechanisms of wear while fatigue processes are ac tivated later in the tests. The effects of diamond-like carbon coating stru cture, surface roughness and lubrication on tribological behaviour are pres ented. Optimal process-structure-property design for vacuum are plasma depo sition is utilized in order to obtain strong adhesion to the titanium alloy substrate. Diamond-like carbon coatings significantly improve the friction and wear performance of the orthopaedic bearing pair and show exceptional promise for biomedical applications. (C) 1999 Kluwer Academic Publishers.