Surface modification of titanium by anodic oxidation in phosphoric acid at low potentials. Part 1. Structure, electronic properties and thickness of the anodic films

Abstract

Titanium surface characteristics determine the degree of success of permanent implants. The topography, morphology of the surface in micro and nano scales, the impurities present and other characteristics are a main concern, and therefore a multi-technique approach is required in order to evaluate modification process effects on the surface. Surface modification of titanium in the nanometrical range was performed by means of anodisation in phosphoric with the aim of improving both the biocompatibility and the corrosion resistance in the biological media. Biocompatible characteristics of the modified titanium surface, as the presence of anatase in the oxide film and the incorporation of phosphate to the surface, were determined. Moreover, the electronic properties of the surface oxide presented a carrier number adequate for biomedical applications. The increase in the film thickness from 3 to 42 nm was estimated from EIS results when anodising potentials from 0 to 30 V were applied, whereas a bi-layer structure of the protective oxides formed was determined.