An experimental study on the fretting corrosion behaviours of three material pairs at modular interfaces for hip joint implants

The fretting corrosion behaviours of Al₂O₃ ceramic/Ti6Al4V alloy, 316 L stainless/Ti6Al4V alloy, and CoCrMo alloy/Ti6Al4V alloy pairs were studied in an in-house developed fretting-corrosion tester. The fretting behaviours were characterized by the F_t-D-N and F_t/F_n curves. The morphology of the worn surface was analyzed by energy dispersive X-ray spectrometry (EDX), a scanning electron microscope (SEM), and a white light interferometer (WLI). The fretting regimes were found to vary from slip regime (SR) to mixed fretting regime (MFR), with an increase in loads for the Al₂O₃/Ti6Al4V and 316 L/Ti6Al4V pairs, while for the CoCrMo/Ti6Al4V pair the fretting always remained in SR. The damage mechanism of the Al₂O₃/Ti6Al4V pair was mainly abrasive wear and corrosive wear, while for the 316 L/Ti6Al4V pair and CoCrMo/Ti6Al4V pair, the wear mechanism was mainly adhesive wear and corrosive wear with slight abrasive wear. The electrochemical impedance spectrum results show that the material transfer layer formed on the surface of the material can protect the material from corrosion for the 316 L/Ti6Al4V and CoCrMo/Ti6Al4V pairs.