Publication
Metallic materials implanted in living tissues are subject to the corrosive environment of body fluids, which constitutes a complex electrolyte critically dependent on each individual person. CoCr alloys are widely used as biomedical prosthesis for hip and knee replacements. The reactivity of the synovial fluid influences the degradation rate of those materials and may modify its electrochemical behaviour thus determining the possible failure of the implant. The aim of this work is to characterize the electrochemical reactivity of fluids extracted from patients with different articular pathologies and prosthesis revisions by electrochemical techniques. The electrochemical behaviour of a commercial CoCrMo alloy will be also studied in the same in-vivo fluids. The electrochemical measurements of CoCr in the in-vivo synovial fluids showed high precision, reproducibility and signal stability. The corrosion behaviour of the alloy involves typical reactions encountered in simulated body fluids (such as passivation, transpassivity, mass transport limited reduction of oxygen, water reduction). Cyclic voltammetry on a platinum electrode shows different electrochemical behavior of the fluid depending on the patient.