In situ characterization of the effects of Nb and Sn on the anatase-rutile transition in TiO2 nanotubes using high-temperature X-ray diffraction

New metastable p-type Ti alloys for biomedical applications containing biocompatible alloying elements such as Nb can present remarkable mechanical behavior. Whenever the performance of an implant produced from p-type Ti alloys is considered, it is crucial to take into account their surface properties because they are intimately associated with osseo-integration. The osseo-integration of orthopedic implant devices made from CP-Ti to p-type Ti alloys depends directly on the properties of the oxide layer formed on their surface. The aim of this study was to investigate the formation of self-organized TiO2 nanotubes by an anodization process on CP-Ti and Ti-35Nb and Ti-35Nb-4Sn alloys (wt.%) and analyze the effects of Nb and Sn additions to CP-Ti on the amorphous-anatase and anatase-rutile phase transformations in TiO2 nanotubes using glazing-angle high-temperature X-ray diffraction. The results obtained suggest that the crystallization of Ti 02 formed on CP-Ti occurs at 225 C, whereas the anatase-rutile transition occurs at 400 C. As Nb was added to Ti, the temperatures at which these phase transformations occur increased. When Sn was added to Ti-35Nb alloy, the kinetics of the phase transformations appeared to decrease. 2014 Elsevier B.V. All rights reserved. (AU)