The effect of titanium support on the morphological properties of growth of titanium-oxide nanotubes and platinum deposit

It is shown that the thickness and structure of the layer of titanium-oxide nanotubes obtained by anodization of titanium foil in fluoride-containing solutions are determined by crystallographic orientation of surface metallic grains. In addition, this orientation appears when platinum deposits are applied onto nanooxide. Optical microimages in polarized light can be used for estimation of the quality of the crystallographic orientation of surface metallic grains, as well as for control of the thickness of oxide nanotubular layers. Shiny grains are characteristic for a nonuniformly (steplike) etched support with formation of a “humpy” light-scattering grain structure. Dull grains usually have the flat (0001) orientation; the process of nanotube growth occurs uniformly over the surface and is considerably hindered, which is probably related to the higher atomic density of the (0001) plane and protective properties of the barrier oxide. It is shown that TiO2 nanotubes are formed at a growing rate on bright grains and grains with the crystallographic orientation allowing formation of a thick oxide layer.