Characterization of Ti-35Nb alloy surface modified by controlled chemical oxidation for surgical implant applications

Titanium-Niobium alloys have been studied for biomedical applications due to their satisfactory biocompatibility. In order to improve the long-term implantation, surface modification techniques have been developed to generate suitable topography, roughness, chemical composition, surface energy, etc. Considering this approach, the present work aimed to characterize Titanium-35Niobium (Ti-35Nb) surface modified by controlled chemical oxidation. Ti-35Nb (wt%) substrates were processed by powder metallurgy. The powders were mechanically mixed, uniaxially cold pressed and sintering at 1300 degrees C/2h. Then, the sintered substrates were immersed in a solution consisting of equal volumes of concentrated H2SO4 and 30% aqueous H2O2 for 4 hours at room temperature under continuous agitation. Sample characterizations were performed by scanning electron microscopy, profilometry, contact angle measurement, X-ray diffraction, and X-ray photoelectron spectroscopy. The results showed that the samples exhibited a microporous structure with micro-roughness on surface, and the beta-Ti phase was stabilized by complete niobium atoms diffusion in titanium matrix. In addition, the chemical treatment successfully modified the Ti-35Nb surface with micropore formation and enhancement of hydrophilic feature and TiO2 and Nb2O5 layer, which can improve the biocompatibility of TiNb alloy implants.