Corrosion resistance assessment of 316LVM under various surface treatments for implantable orthopedic devices

The 316LVM stainless steel, valued for its corrosion resistance and biocompatibility, finds extensive use in orthopaedics, particularly in fabricating intramedullary lengthening nails for procedures. Despite its commendable attributes, susceptibility to localized corrosion, similar to the 316L variant, poses concerns for biomedical applications. This study investigates the corrosion resistance of 316LVM steel and exploring potential enhancement possibilities through specific surface treatments like nitric acid passivation, Diamond-Like Carbon (DLC), and Kolsterising. Evaluation involved both extruded and annealed variants of the steel, the latter aimed at stress relieving. Corrosion and crevice corrosion behaviour were studied implementing various electrochemical polarization techniques (OCP, EIS, PD) accompanied by in depth microstructural characterization techniques. Electrochemical polarization measurements were performed for as-received, annealed, passivated, and surface treated samples in simulated body fluid (SBF). Analysis of polarization curves revealed enhanced corrosion resistance with DLC treatment, evident in increased breakdown potential and reduced corrosion rates. Finally, it was found that the DLC treatment exhibits optimal corrosion resistance. These promising findings signify potential advancements in enhancing corrosion resistance for temporary orthopaedic implants, marking a positive trajectory for future developments in the field.