Corrosion and tribocorrosion behavior of CoCrMo alloys used as hip joint implant materials under simulated body fluids: Effect of proteins and normal load

The release of metal ions and wear debris are raising serious concerns on metal-on-metal (MoM) hip prosthesis. The purpose of this work was to evaluate the corrosion and tribocorrosion behavior, of a low-carbon CoCrMo alloy, as a function of proteins content in the biological fluid and normal applied load. Electrochemical tests were performed to study the corrosion behavior of the alloy, under two simulated body fluids: phosphate buffer solution (PBS) and bovine calf serum (BCS). The tribocorrosion tests were performed using the same solutions, under different loading conditions and tribometer configuration. An attempt was made to evaluate the synergistic interactions between corrosion and wear. The surface characterization of the sample was also studied. The presence of proteins was found to improve the corrosion resistance and passive behavior due to their protective boundary lubricant effect. Normal applied load showed to increase the passive film destruction.