Tribocorrosion Behavior of Forged CoCrMo Alloy for the Artificial Joint Materials

The tribocorrosion behavior of forged CoCrMo alloy in 25% calf serum solution was investigated by the UMT-2 multi-functional friction and wear tester and electrochemical workstation (CHI614E). The morphology of tribocorrosion of forged CoCrMo alloy was analyzed by scanning electron microscopy. The corrosion loss,loss of mechanical wear and loss due to wear-corrosion synergistic interaction were compared systematically. The results show that the corrosion potential (E_corr) of forged CoCrMo alloy in 25% calf serum solution was about -820 mV. The two passivation phenomena occurred in 0.5~0.75 V region. Under the different applied load conditions,the friction coefficients of tribocorrosion were higher than that of the pure sliding. With the increase of applied loads,the friction coefficients of tribocorrosion decreased and the current increased. The loss of mechanical wear increased and the corrosion loss decreased with the increase of applied loads. The loss due to wear-corrosion synergistic interaction accounted for more than 30% of the total loss.