Electrochemical and surface behavior of hydyroxyapatite/Ti film on nanotubular Ti–35Nb–xZr alloys

In this paper, we investigated the electrochemical and surface behavior of hydroxyapatite (HA)/Ti films on the nanotubular Ti–35Nb–xZr alloy. The Ti–35Nb–xZr ternary alloys with 3–10 wt.% Zr content were made by an arc melting method. The nanotubular oxide layers were developed on the Ti–35Nb–xZr alloys by an anodic oxidation method in 1 M H3PO4 electrolyte containing 0.8 wt% NaF at room temperature. The HA/Ti composite films on the nanotubular oxide surfaces were deposited by a magnetron sputtering method. Their surface characteristics were analyzed by field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) and an X-ray diffractometer (XRD). The corrosion behavior of the specimens was examined through potentiodynamic and AC impedance tests in 0.9% NaCl solution. From the results, the Ti–35Nb–xZr alloys showed a solely β phase microstructure that resulted from the addition of Zr. The nanotubular structure formed with a diameter of about 200 nm, and the HA/Ti thin film was deposited on the nanotubular structure. The HA/Ti thin film-coated nanotubular Ti–35Nb–xZr alloys showed good corrosion resistance in 0.9% NaCl solution.