Facile hydrothermal synthesis of TiO2–CaP nano-films on Ti6Al4V alloy

Ti6Al4V alloy was subjected to hydrothermal treatment in the concentrated Ca3(PO4)2, CaHPO4 and Ca(H2PO4)2 solutions for bioactive surface modification. The treated samples are covered by films composed of nano-particles with the size of 60–240 nm. Such film can also be grown on the strut surface of a Ti6Al4V scaffold prepared by electron beam melting (EBM) technology. XPS analysis indicates that Ti element on the surface presents as TiO2, and Ca and P elements are in the form of calcium phosphate. XRD and Raman analyses show that the surface layer is composed of anatase TiO2 and hydroxyapatite. Potentiodynamic polarization test in a Ca-free Hank's balanced solution demonstrates that the treated sample has markedly improved corrosion resistance compared with the polished sample. The present work provides a bioactive surface modification method that is easily-operated, low-temperature, less corrosion, and applicable to porous Ti6Al4V alloy for biomedical applications.