Titanium alloys, particularly Ti6Al4V, are widely used in biomedical applications due to their excellent mechanical properties and inherent biocompatibility. However, enhancing their surface characteristics, such as biocompatibility and corrosion resistance, remains a key challenge for their long-term use in medical implants. In this study, we investigate the effects of rhenium–carbon coatings deposited on Ti6Al4V substrates via magnetron sputtering, incorporating a molybdenum anchoring layer. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analyses confirmed the formation of rhenium carbides, elemental rhenium, and rhenium oxides within the coatings. Despite these successful depositions, scanning electron microscopy (SEM) revealed significant delamination and poor adhesion of the coatings to the Ti6Al4V substrates. Corrosion resistance, evaluated through potentiodynamic polarization tests, showed an increase in corrosion current densities and more negative corrosion potentials, indicating a detrimental effect on the substrate’s corrosion resistance. Biocompatibility assessments using PK15 cells demonstrated a marked decrease in cell viability and metabolic activity, particularly in samples with higher surface roughness. These findings underscore the critical need for the optimization of surface preparation and deposition processes to improve both the adhesion and biocompatibility of rhenium–carbon coatings on Ti6Al4V substrates. Future research should aim to refine coating technique to enhance adhesion, explore the mechanisms of cytotoxicity related to surface roughness, and expand biocompatibility studies across different cell lines and biological environments.

Titanium alloys, notably Ti6Al4V, are frequently employed in biomedical applications due to their high mechanical strength and biocompatibility. But improving their surface qualities like biocompatibility and resistance to corrosion remains a crucial topic of study. This study investigates the effects of rhenium-carbon coatings deposited on Ti6Al4V substrates using magnetron sputtering technique with a molybdenum anchoring layer. Despite successful formation of rhenium carbides, elemental rhenium, and rhenium oxides confirmed by EDS and XRD analysis, the coatings exhibited poor adhesion, resulting in significant delamination as observed in SEM images. Corrosion resistance tests revealed that the coatings adversely affected the Ti6Al4V substrate, as indicated by increased corrosion current densities and more negative corrosion potentials in potentiodynamic polarization tests. Biocompatibility assessments using PK15 cells showed a notable reduction in cell viability and metabolic activity, particularly with coatings of higher surface roughness. These findings underscore the need for improved surface preparation and coating processes to enhance adhesion and biocompatibility of rhenium-carbon coatings on Ti6Al4V substrates. Future research should focus on optimizing coating adhesion, investigating cytotoxicity mechanisms related to surface roughness, and expanding biocompatibility evaluations to various cell types and biological environments.