Metal Release of CoCrMo Alloy in Protein-Rich Solutions – Effect of Irradiation, Sliding and Manufacturing Process
Abstract
CoCrMo alloys, which have excellent corrosion and wear resistance, are widely used for implants in the human body. Even for the most corrosion-resistant alloys, interfacial reactions occur between the metal surface and the biological environment. It is important to investigate the mechanism of corrosion behavior of CoCrMo in protein-rich solutions. This research is focused on the metal release and corrosion behavior of CoCrMo in protein-rich solutions under different simulated conditions and for different manufacturing processes. Implants can sometimes be present in patients who need to undergo cancer radiotherapy. Therefore, the effect of gamma irradiation on the metal release from CoCrMo alloy was investigated. It found that the radiation slightly influenced the extent of metal release from CoCrMo. CoCrMo are used in wearing parts of implants, where they are exposed to friction and a protein-rich environment. Hence, the effect of sliding, protein aggregation and metal precipitation on metal release from CoCrMo were investigated. In this study, metal release under sliding condition was increased in the presence of albumin. However, protein aggregation and metal precipitation result in underestimation of the extent of metal release from CoCrMo in mixed protein solutions. Generally, 3D printers are used for manufacturing implants of various shapes. However, the print direction may affect the properties of CoCrMo. The influence of the manufacturing process on protein-induced corrosion for CoCrMo was minor. All these studies give a deep insight in the extent and mechanism of metal release from CoCrMo in protein-rich solutions, which helps to minimize the failure of implants.