A comparative study of the corrosion performance of titanium (Ti), titanium nitride (TiN), titanium dioxide (TiO2) and nitrogen-doped titanium oxides (N–TiO2), as coatings for biomedical applications

Abstract The performance of four titanium coatings, namely, Ti, TiN, TiO 2 , and N–TiO 2 was assessed in terms of their surface properties and electrochemical corrosion in simulated body fluid in relation to their medical applications. Ti, TiN, TiO 2 , and N–TiO 2 coatings were deposited onto stainless steel substrates by a plasma surface alloying technique. Morphology, composition, and structure were investigated by SEM, GDOES, and XRD. Corrosion resistance results indicated that Ti, TiN, TiO 2 , and N–TiO 2 coatings could achieve higher corrosion polarization resistance and a more stable corrosion potential in the SBF environment than the uncoated stainless steel substrate SS316L. In comparison with the Ti, TiN, and TiO 2 coatings, the N–TiO 2 coating exhibited superior corrosion resistance. This resistance may be attributed to the multilayered structure of the coating (an outer oxidative layer and an inner diffusion zone of Ti and N), which can hinder the diffusion of reactive ions.