INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Film characterization of anodic oxides on Zr and Zr2.5Nb for biomedical applications
Autor/es:
TANO DE LA HOZ M.F.; LAZARTE S.; GOMEZ SANCHEZ A.; CERÉ S.; KATUNAR M.R.
Lugar:
Sevilla
Reunión:
Congreso; EUROCORR 2019; 2019
Institución organizadora:
European Federation of Corrosion
Resumen:
Zirconium and its alloys were developed and successfully used as structural materials in nuclear industry. Later, biocompatibility and osseointegration capability in biological fluids was observed, creating interest for its potential use as permanent implants. In biomedical applications, surface characteristics including morphology, electronic nature and crystalline phases present determines the chances for success in service. Anodization constitutes a surface modification route that allows the design of the structure, chemistry and electronic properties of the films formed by carefully selecting process variables. Previously, we developed well characterized surface conditions with high corrosion resistance and osseointegration rates on pure zirconium. In this work, the surface characterization of Zr2.5Nb alloy was performed and compared with pure zirconium as an initial stage for further in vitro and in vivo studies. The surface morphology of the specimens was observed by scanning electron microcopy. The crystalline phases were determined by Raman spectroscopy and graze angle X-ray diffraction. Anodic polarization curves and electrochemical impedance spectroscopy tests were performed in borax solution. Semi crystalline zirconium oxides were formed on Zr2.5Nb, with monoclinic ZrO2 as the predominant phase. High coverage of the anodic oxide was observed by electron microscopy, whereas current densities in anodic polarization founded were similar to those obtained in pure zirconium. Capacitive films with high impedance corroborates the barrier effect of the surface oxides to charge transfer, with a double layer structure determined from electrochemical impedance results. Finally, the film thickness was estimated from Brug equation and n type semiconductive nature of the oxides was determined from Mott-Schottky experiments.