Tribocorrosion of passive metals in the mixed lubrication regime: theoretical model and application to metal-on-metal artificial hip joints

Wear is a key problem limiting the lifetime and performance of total hip arthroplasty. The synovial fluid, acting as lubricant, can alleviate the wear of implants but also introduces corrosion. The interaction of mechanical wear and electrochemical corrosion, nominally tribocorrosion, has been proposed as one of the crucial degradation mechanisms of implants and recently saw significant progress in mechanistic understanding and modeling. This study presents a predictive wear model based on a mechanistic approach of tribocorrosion and lubrication and taking into account clinical relevant parameters such as normal load, velocity and clearance. Predicted wear rate corresponds well to the running-in wear rate from simulator experimental results and allows to identify the dominating wear mechanism and to evaluate the influence of several parameters.