Initial SO2-induced atmospheric corrosion of ZnAlMg coated steel studied with in situ Infrared Reflection Absorption Spectroscopy

• The initial atmospheric corrosion of ZnAl2Mg2 coated steel in humid air with 80ppb SO2 was studied using in situ Infrared Reflection Absorption Spectroscopy, XRD and SEM. Corrosion products formed in SO2- and SO2 and NaCl containing environments on ZnAl2Mg2 (ZM) were dominated by Mg-containing sulphite and sulphates with sulphite formed mainly initially. The sulphite formation is connected with dissolution of the Mg-containing oxide layer present initially. This is followed by a localised corrosion process where Mg rich phase in the binary eutectic microstructure is dissolved anodically while the Zn-rich phase is the site for the cathodic oxygen reduction.

Ämnesord

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

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

Nyckelord

Metal coatings

IR-spectroscopy

XRD

Atmospheric corrosion

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)