Corrosion protection performance of thickened oxide conversion coatings containing vanadium ions formed on aluminum composites

Abstract:

A vanadium-based filming treatment has been investigated as a replacement for chromate conversion treatments on AA 6061 T6-10% Al2O3. The corrosion resistance was measured using AC impedance spectroscopy and DC polarization in 3.5% NaCl. A treatment process which thickens the existing aluminium oxide film and incorporates vanadium ions is being proposed. The process involves cleaning, etching, oxide thickening by immersion in boiling deionized water, and a sealing stage in vanadate. The surface morphologies of the treated samples were investigated using SEM and XPS. The oxide-thickening step of the material was found to have a vital effect on the corrosion resistance of the conversion coating produced. It has been shown that the vanadium plays an important role in rejecting the chloride ions from the material surface. Moreover, vanadium is incorporated through the pores of the thickened oxide layer to form an AI-V-oxide layer. This layer showed a promising corrosion resistance even after 60 days of immersion in NaCl.

Año de publicación:

2001

Keywords:

Fuente:

scopus