Corrosion inhibition of aluminium alloy AA6063-T5 by vanadates : Local surface chemical events elucidated by confocal Raman micro-spectroscopy

• Chemical interactions between aqueous vanadium species and aluminium alloy AA6063-T5 were investigated in vanadate-containing NaCl solutions. Confocal Raman and X-ray photoelectron spectroscopy experiments were utilised to gain insight into the mechanism of corrosion inhibition by vanadates. A greenish-grey coloured surface layer, consisting of V+4 and V+5 polymerized species, was seen to form on the alloy surface, especially on top of cathodic micrometre-sized IMPs, whereby suppressing oxygen reduction kinetics. The results suggest a two-step mechanism of corrosion inhibition in which V+5 species are first reduced to V+4 or V+3 species above cathodic IMPs, and then oxidized to mixed-valence V+5/V+4 polymerized compounds. 

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Nyckelord

A. Alloy

A. Aluminium

B. Raman spectroscopy

B. SEM

B. XPS

C. Vanadate inhibitor

Corrosion inhibitors

Electrolytic reduction

Sodium alloys

Sodium chloride

Transition metal compounds

Vanadium alloys

X ray photoelectron spectroscopy

Chemical interactions

Corrosion inhibition

Local surfaces

Mechanism of corrosion

Oxygen reduction kinetics

Two-step mechanisms

Vanadium species

Aluminum corrosion

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