Electrochemical Surface Treatment to Enhance Corrosion Resistance and Bioresistance of Medical-Grade Stainless Steels

The room-temperature eco-friendly electrochemical surface treatment of medical-grade stainless steels in ethaline, a eutectic mixture of choline chloride and ethylene glycol in a molar ratio of 1:2, is investigated in this work. High levels of brightness, smoothness and corrosion resistance of the surfaces of the stainless steels Mn AISI, AISI 316Ti, and AISI 304 can be achieved by using the technique of anodic treatment in ethaline. The surface smoothing of the steel samples due to the dissolution of defects and inhomogeneities, and the enrichment of the electropolished surfaces with chromium and nickel, resulted in increased corrosion resistance and bioresistance. The results of the experiments demonstrated that with anodic treatment in ethaline it is possible to decrease the amount of the Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans microorganisms on the surfaces of the steel samples by a factor of up to 75. Thus, the deep eutectic solvent ethaline is a highly promising medium for significantly improving corrosion resistance and bioresistance of medical-grade stainless steels by anodic treatment.