Titanium and Ti alloys have been used extensively as bone-implant materials due to their high strength-to-weight ratio, good biocompatibility and excellent corrosion resistance. In this work we have investigated the effects of the beta-stabilizing element Nb on the morphology of nanotubes formed on Ti-xNb alloys using 1.0 M H(3)PO(4) electrolyte containing 0.8 wt.% NaF and various electrochemical methods. Oxide layers consisting of highly ordered nanotubes with a wide range of diameters (approximately 55-220 nm) and lengths (approximately 730 nm-2 mu m) can be formed on alloys in the Ti-xNb system as a function of Nb content The nanotubes formed on the Ti-Nb alloy surface were transformed from the anatase to rutile structure of titanium oxide. The titanium oxide nanotube surface was observed to have lower corrosion resistance in 0.9% NaCl solution compared to titanium oxides surfaces on Ti-xNb alloys without the nanotube morphology. (c) 2009 Elsevier B.V. All rights reserved.