Investigation and In Vitro Studies of a ZrO2/g-C3N4 Composite Coated on 316L Stainless Steel for Biomedical Applications

Abstract

The advancement of smart coatings for bioimplants has yielded a combination of biocompatibility and corrosion resistance. 316L stainless steel (316LSS) is a commonly used commercial implant, but it has limitations in biocompatibility and durability, which hinders the widespread utilization of 316LSS alloys. In this study, the 316LSS alloy is coated with a mixture of zirconium dioxide (ZrO₂₎, prepared using the sol–gel method, and graphitic carbon nitride (g-C₃N₄), synthesized by thermal polymerization. XRD and Raman analyses confirmed the crystal structure and purity of the synthesized samples. The corrosion resistance property was assessed using OCP, POL, and PEIS. The findings demonstrate that the ZrO2/g-C₃N₄-coated 316LSS shows significantly enhanced corrosion resistance and biocompatibility in a simulated body fluid. The in vitro bioactivity test reveals that the ZrO₂/g-C₃N₄ coating leads to the formation of an apatite layer over the surface of 316LSS. The elemental composition of the HAP deposition was confirmed by Raman analysis. The results suggested that the ZrO2/g-C₃N₄–coated 316LSS substrate is a promising material for use in biomedical applications.