Study On The Swing Tribocorrosion Behaviors Of 316L/UHMWPE And CoCrMo/UHMWPE Contact Interface

When the artificial joint prosthesis is implanted into the human body, the wear and corrosion of artificial joint materials are inevitable. The isolated research on wear and corrosion behaviors is difficult to fully reveal the biological tribocorrosion phenomenon of the contact interface between artificial joint materials. At present, most of researches on friction behaviors of artificial joint materials focused on the tangential sliding friction, and few of researches focused on the swing friction. Therefore, it’s necessary to carry out the research on swing tribocorrosion behaviors of the contact interface between artificial joint materials. The 316L/UHMWPE and CoCrMo/UHMWPE were selected as research objects in this paper, and the swing tribocorrosion behaviors of the objects and the wear/corrosion mechanism were studied systematically. The main conclusions are as follows:The results reveal that the coefficient of friction can be divided into rising stage and stable stage. The stable value of COF grows with the increases of axial load and swing angular displacement. On the same load conditions, the stable COF value of CoCrMo/UHMWPE is lower than 316L/UHMWPE. The results of UHMWPE wear loss reveal that there is a linear positive correlation between the wear loss and test cycles within a certain range. The UHMWPE wear loss increases with the increases of axial load and angular displacement. The wear loss of UHMWPE coupled with CoCrMo is higher than coupled with 316 L. The wear mechanisms of 316 L and CoCrMo alloy mainly are abrasive wear. And the wear mechanisms of UHMWPE are combined with adhesive and fatigue wear. The surface roughness of UHMWPE decreases because of the stress and wear, while the surface roughness of 316 L and CoCrMo increases in the end of experiment.The results of Ecorr tests show that there is a significant shift of Ecorr to the negative direction during the tribological tests, which indicate that the mechanical wear can increase the corrosion tendency of 316 L and CoCrMo. The results of Icorr tests show that there is a significant shift of Icorr to the positive direction during the tribological tests, indicating that the mechanical wear can promote the corrosion rate of 316 L and CoCrMo. It’s also found during the tests that the corrosion current of 316 L is higher than that of CoCrMo, which means the resistance of CoCrMo is better than 316 L. It’s observed that the corrosion potential increases and the corrosion current decreases when the tests ceased, indicating that the passive films on the alloys recover once the test stops.The quantitative analysis reveals that the total mass loss through corrosion during the tribocorrosion tests is triple than that during the static corrosion. The mass loss through corrosion of CoCrMo is lower than that of 316 L. Compared with the static corrosion, the ions release concentration during the tests increased substantially, revealing that the mechanical wear can enhance the corrosion of the artificial joints materials. The test results reveal that there are interaction effects between the wear and corrosion. In this paper the interaction effects has been mainly reflected in the promotion of wear to corrosion.