6533b82dfe1ef96bd129118f
RESEARCH PRODUCT
In situ characterization of passive films on al-ti alloy by photocurrent and impedance spectroscopy
Carmelo SunseriF. Di QuartoSalvatore PiazzaG.lo BiundoM. C. Romanosubject
PhotocurrentMaterials scienceGeneral Chemical EngineeringMetallurgyAlloyOxideGeneral ChemistryDielectricengineering.materialDielectric spectroscopychemistry.chemical_compoundchemistryengineeringMixed oxideGeneral Materials ScienceSurface layerComposite materialDissolutiondescription
Abstract The anodic behaviour of an Al-Ti alloy (Ti-48Al-1V, atomic %) was investigated in different aqueous electrolytes. In all cases the alloy was passive owing to the growth of a barrier-like oxide film according to the high field mechanism. The study of the growth curves suggests partial dissolution of the film during the formation process in acidic solution. The kinetic parameters for film formation have been estimated in neutral solutions and the dielectric constant of the passive layer was roughly estimated. The in-situ characterization of the passive film revealed a n-type behaviour only for very low thicknesses, whilst thicker films showed insulator-like characteristics. The analysis of the photocurrent spectra suggests that the composition of the surface oxide does not change in a large thickness interval since the very thin initial layers formed by simple immersion of the alloy in solution. From the values of the threshold energy derived from both anodic and cathodic spectra recorded in different conditions it is postulated that this passive film consists of a mixed oxide of the main components of the alloy. A more complex behaviour was observed at higher film thicknesses, which reveals some modification in the properties of the surface layer.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1998-07-01 | Corrosion Science |