Different applied potentials have been employed in a two-step anodization process, utilizing a 1 M H3PO4 electrolyte and a solution containing this electrolyte and 0.8 wt.% NaF, to control the shape and morphology of oxide nanotubes on coatings for ternary Ti-30Ta-xZr alloys. The ternary alloys were manufactured using an arc furnace, and corrosion testing was carried out using a potentiostat. The microstructures of the Ti-30Ta-xZr alloys had a needle-like structure, and the lath thickness of the alpha' phase increased as the Zr content increased. The microstructures of Ti-30Nb-xZr alloys had equiaxed grains. The Ti-30Nb-xZr alloys showed smaller micropores and nanotubes compared to the Ti-30Ta-xZr alloys. The Ti-Nb(Ta)-Zr alloys tended to have improved corrosion resistance with increasing Zr content. (C) 2014 Elsevier B.V. All rights reserved.