Influence of corrosion behavior of Ti-based PVD coatings on 316L SS for biomedical implants

Abstract

Background 316L stainless steel (SS) is widely used in biomedical implant applications because of its excellent mechanical properties, corrosion resistance, biocompatibility, and cost-effectiveness. However, its long-term performance in physiological environments is limited by localized corrosion, ion release, and inadequate surface interactions with biological tissues. Surface modification using Ti-based physical vapor deposition (PVD) coatings has emerged as a promising strategy to enhance the corrosion resistance and durability of implant materials. Objective This study aimed to investigate the effect of Ti-based PVD coatings, namely TiCoCr, TiN, and TiO2, on the corrosion behavior of 316L SS under simulated physiological conditions. Methods TiCoCr, TiN, and TiO2 coatings were deposited onto 316L SS substrates using the PVD technique. The corrosion performance of the coated and uncoated samples was evaluated in phosphate-buffered saline (PBS), Hanks’ solution, and Ringer's solution at 37 °C. Electrochemical corrosion parameters, including corrosion potential and corrosion current density, were analyzed to assess the effectiveness of the coatings. Results All Ti-based coatings improved the corrosion resistance of 316L SS compared with the uncoated substrate. Among the investigated coatings, the TiCoCr coating deposited for 90 min exhibited the best corrosion performance. In Ringer's solution, the coating showed a corrosion potential of −0.0504 V and a corrosion current density of 4.74 × 10−6 A/cm2. In Hanks’ solution, the same coating demonstrated a corrosion potential of −0.1815 V and a corrosion current density of 5.0537 × 10−6 A/cm2. The enhanced corrosion resistance was attributed to the protective and stable nature of the Ti-based coating layer. Conclusion The TiCoCr, TiN, and TiO2 PVD coatings significantly enhanced the corrosion resistance of 316L SS in simulated physiological environments. Among them, the TiCoCr coating demonstrated superior corrosion protection, indicating its strong potential for improving the long-term reliability and performance of biomedical implants.