Surface characterization, electrochemical behaviour and cytotoxicity of UNS S31254 stainless steel for orthopaedic applications

Abstract

The surface characterization and electrochemical behaviour of UNS S31254 (254 SS) have been performed in 0.15 mol L 1 NaCl medium in order to evaluate its application as orthopaedic implants. Polarization curves, chronoamperometry, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy were used for characterizing the samples. A cytotoxicity test was also performed to study the biocompatibility of the proposed steel as biomaterial. The electrochemical behaviour of 254 SS was compared to that observed for ISO 5832-9 and ASTM F138 stainless steels, used in orthopaedic implants. 254 SS is similar to ISO 5832-9 SS: it is passivated on the potential range between the corrosion and the transpassivation potential. Mo (VI) forms an outer layer which blocks Cr (VI) dissolution. Cytotoxicity test showed no cytotoxic character of 254 SS.