Adsorption behavior regulates the frictional response of a solid-liquid system: A case study of the ZrN-Cu/bovine serum albumin solution system

Coated artificial joint implants and the surrounding tissue fluid are a solid-liquid system, and the tribological behavior of this system is an important factor to evaluate the service performance of the implants, which has received continuous attention. Here, we investigated the tribological behavior of ZrN-Cu films in bovine serum albumin(BSA) solution. The results show that Cu can effectively improve the tribological performance of the ZrN-Cu/BSA system. Through the investigation of the tribochemical products, adsorption behavior, hertzian contact stress, flash temperature, etc., we elucidated the improving mechanism of the ZrN-Cu/BSA system, forming a carbon-based transfer film deriving from BSA with the catalytically active ZrN-Cu film and a stable surface adsorption layer due to Cu separating the contact surface.