Localized Atmospheric Corrosion of Magnesium-Aluminum Alloys Produced by Semisolid Casting: A 2D and 3D Investigation
Artikel i vetenskaplig tidskrift, 2021

The localized corrosion of the two magnesium-aluminum alloys AM50 and AZ91 produced by a semisolid casting method was investigated under atmospheric corrosion conditions, in the presence of NaCl. Gravimetry confirmed the beneficial effect from ambient levels of carbon dioxide (CO2) in suppressing corrosion through the formation of magnesium hydroxy carbonates. Both 2D and 3D characterization revealed that ambient CO2 has a strong influence on the morphology and rate of localized corrosion. In CO2-free atmosphere, the alloys suffered localized corrosion resulting in clustered and interconnected cavities that extended deep into the material. In contrast, corrosion in the presence of ambient levels of CO2 (400 ppm) resulted in evenly distributed shallow corrosion sites. The results indicate that CO2 neutralizes the cathodic areas resulting in diminished cathodic activity and inhibiting NaCl(aq) droplet coalescence.

atmospheric corrosion

corrosion morphology

magnesium-aluminum alloys

3D imaging

localized corrosion

casting

Författare

M. Shahabi-Navid

Volvo Group

Mats Halvarsson

Chalmers, Fysik, Mikrostrukturfysik

Jan-Erik Svensson

Chalmers, Kemi och kemiteknik, Energi och material, Oorganisk miljökemi

A. Allanore

Massachusetts Institute of Technology (MIT)

N. Birbilis

Australian National University

Lars-Gunnar Johansson

Chalmers, Kemi och kemiteknik, Energi och material, Oorganisk miljökemi

M. Esmaily

Massachusetts Institute of Technology (MIT)

Corrosion

0010-9312 (ISSN)

Vol. 77 2 242-253

Ämneskategorier

Annan kemi

Metallurgi och metalliska material

Korrosionsteknik

Infrastruktur

Chalmers materialanalyslaboratorium

Styrkeområden

Materialvetenskap

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Senast uppdaterat

2021-05-31