Electrochemical behaviour and microstructural characterization of different austenitic stainless steel for biomedical applications

Austenitic stainless steels, specified as ASTM F138, ASTM F1586, and ASTM F2581, underwent a comparative study, including the analyses of microstructure, crystalline phases, and Vickers microhardness. The corrosion resistance was investigated by anodic polarization curves and electrochemical impedance spectroscopy using the 0.9% NaCl solution and simulated body fluid (SBF). All samples exhibited only the austenite phase and the Vickers microhardness was influenced by high nitrogen content addition. Independent on the electrolytic solution type, the ASTM F1586 and ASTM F2581 steels had better corrosive resistance performance from the anodic polarization results. However, ASTM F2581 steel presented the passive film with better protective capacity in the saline solution while ASTM F1586 had better performance in the SBF.