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

Resumo

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 1300ºC/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 β-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.
Keywords: titanium-niobium alloy, powder metallurgy, controlled chemical oxidation, biomaterial.