Elastic modulus and hardness of bioactive Ti obtained by anodic oxidation using Ca/P-based solutions

Anodic oxidation is a promising technique to become titanium surfaces bioactive, by simultaneously changing the surface morphology, structure and chemical properties. Calcium and phosphorus based electrolytes were used to produce anodic films on c.p. Ti with two different current densities, 150 mA/cm2 and 300 mA/cm2. Morphology and structure were examined by SEM, EDS and XRD, and elastic modulus and hardness of the surfaces by instrumented indentation. Besides rutile and anatase TiO2 phases, hydroxyapatite was also identified on the films, as well as the segregation of very soft Ca and P-rich zones. Low values for the elastic modulus and hardness values close to the Ti corroborate to the applicability of Ca and P based TiO2 anodic films in biomedical titanium implants.