Film growth and alloy enrichment during anodizing AZ31 magnesium alloy in fluoride/glycerol electrolytes of a range of water contents

0472822 - ÚFM 2017 RIV GB eng J - Journal Article
Němcová, A. - Galal, O. - Skeldon, P. - Kuběna, Ivo - Šmíd, Miroslav - Briand, E. - Vickridge, I. - Ganem, J.-J. - Habazaki, H.
Film growth and alloy enrichment during anodizing AZ31 magnesium alloy in fluoride/glycerol electrolytes of a range of water contents.
Electrochimica acta. Roč. 219, NOV (2016), s. 28-37. ISSN 0013-4686. E-ISSN 1873-3859
Institutional support: RVO:68081723
Keywords : magnesium * anodic film * enrichment
Subject RIV: JK - Corrosion ; Surface Treatment of Materials
Impact factor: 4.798, year: 2016

The effect of anodizing AZ31 magnesium alloy in a fluoride/glycerol electrolyte containing from 1 to 40 vol.% water on the compositions of the anodic film and the underlying alloy has been investigated. A range of constant current densities and water contents of the electrolyte were employed. Scanning and transmission electron microscopy, with energy-dispersive X-ray spectroscopy, X-ray diffraction and ion beam analyses were used to analyse the anodized alloy. Barrier films, containing fluoride and oxide species, were formed above the matrix, at high current efficiency; a porous film was formed above Al-Mn intermetallic particles. The current density and the water content of the electrolyte affected the O:F atomic ratio and the ionic transport in the films. Significant enrichments of zinc and aluminium were generated in a thin layer of the matrix immediately beneath the film under all conditions of anodizing, with the enrichment of zinc reaching 6.2 x 10(15) at cm(-2) in the enriched alloy layer. The cause of the enrichments and the consequences to film growth are discussed.
Permanent Link: http://hdl.handle.net/11104/0270046