The Influence of SO2 on the Corrosion of Mg and Mg-Al Alloys
Journal article, 2015

The SO2-induced atmospheric corrosion of some magnesium-aluminum (Mg-Al) alloys, including Mg alloy AZ91D, and commercially pure Mg (CP Mg) was investigated using well-controlled laboratory exposures and included real-time measurements of SO2 deposition. The influence of SO2 concentration, alloy composition, humidity, and ppb level additions of O-3 or NO2 on the rate of SO2 deposition was investigated. SO2 accelerates the corrosion of Mg and Mg alloys causing localized corrosion, MgSO(3)6H(2)O being the dominant corrosion product. At 60% RH, traces of O-3 or NO2 strongly increased both the SO2 deposition and the corrosion rate. The rate of SO2 deposition was strongly dependent on humidity; at 70% RH and higher the SO2 deposition rate was very rapid and constant in time while it was transient below 50% RH. At 60% RH, a change from transient to rapid, steady-state, SO2 deposition occurred. The sudden activation is explained by the onset of electrochemical corrosion. The activation behavior was shown to depend on SO2 concentration, the thickness of the surface film and by the presence of ambient O-2.

Author

Mohsen Esmaily

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

D. B. Blucher

SINTEF Materials and Chemistry

R. W. Lindstrom

Royal Institute of Technology (KTH)

Jan-Erik Svensson

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

Lars-Gunnar Johansson

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

Journal of the Electrochemical Society

0013-4651 (ISSN)

Vol. 162 6 C260-C269

Subject Categories

Metallurgy and Metallic Materials

DOI

10.1149/2.0801506jes

More information

Latest update

4/20/2018