SLIDING WEAR STUDIES OF SELECTED NITRIDE COATINGS AND THEIR POTENTIALFOR LONG-TERM USE IN ORTHOPEDIC APPLICATIONS

In the area of orthopaedic implants, particularly total hip joint repl acements, a metal-plastic combination is still the most popular choice consisting of a femoral head fabricated from 316L stainless steel, Ti alloy or Co-Cr alloy in contact with an ultra-high molecular weight p olyethylene (UHMWPE) acetabular cup. It is recently considered that we ar of the UHMWPE cup is of major concern. Generation of the wear debri s can have adverse effects on the body, both localized and systemic. I t is envisaged that wear of the prosthetic components, particularly th ose fabricated from UHMWPE can be reduced through the use of surface c oatings. The aim of this investigation was to deposit a selection of r efractory element nitride-based coatings (TiN, TiAIN, ZrN) onto 316L s tainless steel substrates, using physical vapour deposition (PVD) tech nology and to study their sliding wear behaviour in contact with both UHMWPE and 316L stainless steel pins, using a pin-on-plate testing rig . Tests were conducted in Ringers solution and Ringers solution plus b one cement particles. The volume of material removed from the pins ser ved as an indication of their wear behaviour. Wear mechanisms were ide ntified using scanning electron microscopy. The results of these findi ngs and the potential for these coatings to be used in orthopaedic app lications are discussed.