Influence of electrochemical conditions on CoCrMo behaviour in simulated body fluid by step polarization technique

摘要

Corrosion processes occurring at implant surfaces, the role of oxide films in the corrosion process, alloy biocompatibility and the electrochemical response of alloys to mechanical or electrical transients are all important in the behaviour and success of implant alloys. Most transition metal alloys used in medicine (i.e. Titanium, CoCrMo alloys, stainless steels) have a passive film which spontaneously forms on the surface of the alloy and it provides a kinetic barrier to corrosion reactions. Oxide film structure and morphology are susceptible to the potential which exists across the alloy-solution interface. The present study presents an electrochemical technique based on the application of a potential step and measuring the current transient response to the step in potential. Electrochemical Impedance Spectroscopy (EIS) was carried out in order to provide information concerning the electrical character of the interface. The current density response and the properties of the interface (biomaterial/body fluid) depends on the solution chemistry and the way potential is achieved.