Corrosion behaviour of thermally sprayed zinc-aluminium-coatings in short-term corrosion tests

By alloying aluminium to zinc the corrosion resistance can be increased in a multiplicity of media. Thermally sprayed ZnAl 15-coatings show a higher corrosion resistance than thermally sprayed zinc- or hot dip galvanized coatings. This paper presents the results of short term corrosion tests (salt spray test, Kesternich test) with sprayed ZnAl-coatings with an aluminium content of 2 to 50 M.-%. The investigations verify very clearly the influence of aluminium on the corrosion behaviour. Depending on the aluminium content the corrosion resistance shows a maximium with a medium content of about 15 or 22 M.-%.