Electrochemical and Optical Properties of Thin Oxide Layers Formed on Fresh Titanium Surfaces in Acid Solutions

Abstract

Optical properties and thicknesses of thin oxide layers formed electrochemicallyon Ti surfaces which were exposed by abrasion in situ were evaluatedaccording to results of ellipsometric and reflectometric measurements.It is shown that the optical as well as some other physical propertiesof the thin oxide films are close to those of bulk Ti oxides and,hence, deviations of their electrochemical characteristics from thoseof bulk TiO//2 are most probably due only to their small thicknesses.Electroreduction of such films was also traced by the optical meansand could be shown to result, under certain conditions, in some thinningand, especially, in the increase of the extinction coefficient ofthe film. The effect of such a reductive treatment on the electrochemicalcharacteristics of the oxide layer is also discussed.