Serum Protein Effects on Polarization Behavior of 316L Stainless Steel

This investigation examined the effects of serum proteins addition on the anodic and cathodic polarization behavior of implant alloy 316L stainless steel in saline. Cyclic anodic potentiodynamic polarization was used to determine the four critical parameters associated with passive film breakdown and repassivation: corrosion potential, pitting potential, repassivation potential, and reverse scan hysteresis. Cathodic potentiodynamic polarization was used to study the effects of serum proteins on the Tafel slope and limiting current density of the reduction reaction. Three different conditions of solution purging were investigated. Results were compared with in vivo (hamster) tests. The corrosion potential was significantly affected by aeration conditions in saline as well as in 10% serum. The pitting potential was shifted marginally in the positive direction by serum proteins. While proteins did not affect the cathodic reduction mechanism, their adsorption decreased the reduction kinetics.