title: Self-organized nanotubular oxide layers on Ti-6Al-7Nb and Ti-6Al-4V formed by anodization in NH4F solutions.
abstract: The present work reports the fabrication of self-organized porous oxide-nanotube layers on the biomedical titanium alloys Ti-6Al-7Nb and Ti-6Al-4V by a simple electrochemical treatment. These two-phase alloys were anodized in 1M (NH(4))(2)SO(4) electrolytes containing 0.5 wt % of NH(4)F. The results show that under specific anodization conditions self-organized porous oxide structures can be grown on the alloy surface. SEM images revealed that the porous layers consist of arrays of single nanotubes with a diameter of 100 nm and a spacing of 150 nm. For the V-containing alloy enhanced etching of the beta phase is observed, leading to selective dissolution and an inhomogeneous pore formation. For the Nb-containing alloy an almost ideal coverage of both phases is obtained. According to XPS measurements the tubes are a mixed oxide with an almost stoichiometric oxide composition, and can be grown to thicknesses of several hundreds of nanometers. These findings represent a simple surface treatment for Ti alloys that has high potential for biomedical applications.
authors.affiliation: Department of Materials Science, WW4-LKO, University of Erlangen-Nuremberg, Martensstrasse 7, D-91058 Erlangen, Germany.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Macak
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tsuchiya
authors.forename: Luciano
authors.initials: L
authors.lastname: Taveira
authors.forename: Andrei
authors.initials: A
authors.lastname: Ghicov
authors.forename: Patrik
authors.initials: P
authors.lastname: Schmuki
mesh_terms: D000497:Alloys; D064751:Ammonium Compounds; D005459:Fluorides; D008855:Microscopy, Electron, Scanning; D043942:Nanotubes; D010087:Oxides; D000644:Quaternary Ammonium Compounds; D014025:Titanium
chemical_list: D000497:Alloys; D064751:Ammonium Compounds; D010087:Oxides; D000644:Quaternary Ammonium Compounds; C070282:Ti-6Al-7Nb alloy; C031462:titanium alloy (TiAl6V4); C024822:ammonium fluoride; D014025:Titanium; D005459:Fluorides