Tribocorrosion in implants-assessing high carbon and low carbon Co-Cr-Mo alloys by in situ electrochemical measurements

Tribocorrosion is defined as the chemical-electrochemical-mechanical process leading to degradation of materials in tribological contact immersed in a corrosive environment. Degradation results from the combined action of corrosion and mechanical loading and it is well-known that synergistic effects can accentuate the wear-corrosion rate. While the role of lubrication in reducing wear has been identified, there are still some key unanswered questions in relation to the importance of wear/corrosion interactions. In this study in situ electrochemical measurements have been made to isolate corrosion and corrosion-enhanced wear/tribology damage mechanisms on high carbon CoCrMo and low carbon CoCrMo alloys. Tests are carried out in three different biological solutions: 50% calf bovine serum, Dulbecco's Modified Eagle's Medium (DMEM) and 0.36% NaCl solution at 37 °C with the specific objective being to attempt to isolate the effects of proteins and amino acid species in wear-corrosion. In this paper, a detailed analysis of corrosion/wear interactions is presented, which facilitates discussion of exactly how corrosion and wear processes interact and the role of the lubricating fluid in this respect.