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

Abstract The porous titania growth during electrochemical anodization of titanium films and foils in the 0.1 M ammonium fluoride (FNH 4 ) 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.