Metal‐Driven Autoantifriction Function of Artificial Hip Joint

Abstract The service life of an artificial hip joint is limited to 10–15 years, which is not ideal for young patients. To extend the lifespan of these prostheses, the coefficient of friction and wear resistance of metallic femoral heads must be improved. In this study, a Cu‐doped titanium nitride (TiN_X–Cu) film with “autoantifriction” properties is deposited on a CoCrMo alloy via magnetron sputtering. When delivered in a protein‐containing lubricating medium, the Cu in TiN_X–Cu quickly and consistently binds to the protein molecules in the microenvironment, resulting in the formation of a stable protein layer. The proteins adsorbed on the TiN_X–Cu surface decompose into hydrocarbon fragments owing to the shear stress between the Al₂O₃/TiN_X–Cu tribopair. The synergistic effect of the catalysis of Cu and shear stress between the Al₂O₃/TiN_X–Cu tribopair transforms these fragments into graphite‐like carbon tribofilms with an antifriction property. These tribofilms can simultaneously reduce the friction coefficient of the Al₂O₃/TiN_X–Cu tribopair and enhance the wear resistance of the TiN_X–Cu film. Based on these findings, it is believed that the autoantifriction film can drive the generation of antifriction tribofilms for lubricating and increasing the wear resistance of prosthetic devices, thereby prolonging their lifespan.