Hydroxylation and crystallization of electropolished titanium surface
1992; Elsevier BV; Volume: 42-44; Linguagem: Inglês
10.1016/0304-3991(92)90335-h
ISSN1879-2723
AutoresMarc Jobin, M. Taborelli, R. Emch, Frédéric Zenhausern, P. Descouts,
Tópico(s)Electrodeposition and Electroless Coatings
ResumoSurface properties and dissociative chemisorption of water on titanium-oxide surfaces are of particular interest for the biocompatibility of this material. Scanning force microscopy images of electropolished titanium samples and of thin films of titanium evaporated under vacuum show a similar topography with a grain size of 30 nm. Mass spectrometer thermal desorption spectroscopy displays two peaks for e/m = 18, at 380 and 520 K corresponding to adsorbed water molecules and hydroxyl groups, respectively. Auger spectra show the segregation toward the surface of chlorine from the metal-oxide interface upon heating at 720 K and of sulphur from the bulk after annealing at 950 K. The oxygen diffusion from the surface toward the bulk during the heating process induces a metallic behaviour of the surface layer which is revealed by tunneling spectroscopy: the semiconducting gap present in dI/dV curves for the air-exposed sample vanishes upon annealing. STM images of the annealed surface show the presence of tiny crystallites of a few nm in size.
Referência(s)