The effect of sulphate, phosphate, nitrate and acetate on the corrosion behaviour of ZnAl–Mg hot‐dip galvanised steel

In this work the hot‐dip galvanising coating ZnAl2Mg2 was tested against the reference material ZnAl0.2 in nonstandardised salt spray test. In those tests the samples were exposed to the sodium salts of sulphate, nitrate, phosphate and acetate. The corrosion products formed on the alloys were analysed with XRD. Additionally the corrosion behaviour of the samples was investigated by studying cross‐section cuts with SEM. With this information the corrosivity of the different anions in relation to chloride ions and their corrosion behaviour could be determined.