Surface modification of zirconium by acidic anodization

GOMEZ SANCHEZ, ANDREA; DUFFÓ, GUSTAVO; CERÉ, SILVIA; ORELLANO, JUAN CARLOS

Humacao, Puerto Rico

Otro; Pan American Advanced Studies Institute (PASI): Nano-Bio. The intersection of Bio, Condensed Matter and Solid State Physics; 2010

THE UNIVERSITY OF PUERTO RICO AT HUMACAO

The surface characterization of titanium and zirconium prior and before different surface modification processes is presented in order to use them as permanent implant biomaterials. The influence of surface characteristics to the in vivo performance of both metals is studied. An “island” growing anodic film was verified on both material surfaces modifying the topography by enhancement of roughness. Zirconium surface is more affected by this topographic modification than titanium. The incorporation of phosphorous on the anodic films was verified. This incorporation is beneficial since Ca and P rich compounds are thought to be precursors in osteogenesis. In vitro studies include electrochemical impedance spectroscopy and polarization curves, and their evolution during immersion time in simulated body fluid solution (SBF) in order to analyze the corrosion resistance of the film and the ability to promote the formation of hydroxyapatite on the surface. Electrochemical studies show a better performance of zirconium in the as received and anodized conditions when compared with titanium. In SBF zirconium presents a high corrosion resistance with low ion release rate. The best surface modification prospects, according to in vitro tests, were tested on Hokkaido rats to study the osseointegration. The biological characterization involves the histological examination of the bone – implant interface. The degree of mineralization and stiffness of the newly formed tissue is analyzed by instrumented nanoindentation.