Sol–gel preparation and properties of Ag–TiO2 films on surface roughened Ti–6Al–4V alloy

Ag–TiO2 films (Ag/Ti = 3·3, 9·1 at-%) were sol–gel coated on Ti–6Al–4V alloy that had been surface roughened by the NaOH–HCl treatment for antibacterial applications. Scanning electron microscopy observation showed that pore size of the surface layer of NaOH–HCl treated Ti–6Al–4V alloy increased with the NaOH concentration. Ag–TiO2 films on the surface roughened substrate were adherent and crack-free. X-ray photoelectron spectroscopy and Auger electron spectroscopy analyses indicated that Ag existed in metallic state, and the films completely covered the roughened substrate. X-ray diffraction peaks of the substrate and anatase TiO2 were detected. The Ag–TiO2 films on the roughened substrate exhibited good adhesion quality and high cohesion strength in the indentation test. The potentiodynamic polarisation test showed that the TiO2 and Ag–TiO2 films improved corrosion resistance of the substrate.