Effect of the electrolyte temperature on the formation and structure of porous anodic titania film

The porous titania growth during electrochemical anodization of titanium films and foils in the 0.1 M ammonium fluoride (FNH4) solution in ethyleneglycol has been studied in the temperature range from − 5 °C to + 20 °C. Titania films with a smooth tubular morphology was found to be formed at the electrolyte temperatures below 0 °C. The growth rate was as high as 1.5 μm/min provided that the tube diameters were up to 300 nm and the film porosity was less than 1%. Porous titanium anodization at the electrolyte temperature of 0 °C and below induces formation of porous titania with a structure close to ideal packed hexagonal prisms with a smooth tubular surface. The mechanism of the appearance of such structure is discussed.

► Porous titania with an ordered hexagonal structure ► The approach to form the porous titania doped with carbon up to 18 at.% ► The record values of titanium anodization process have been reached. ► The record values of titania parameters have been obtained.