2007 Volume 56 Issue 9 Pages 414-419
An outdoor exposure and a simulated airborne sea salt corrosion test were carried out to investigate the effect of Al content of Mg-Al-Zn alloys on atmospheric corrosion. In both of the corrosion tests, the alloy containing high Al had the superior corrosion resistance. In the outdoor exposure, Al was concentrated in the surface film during the exposure, which has the beneficial effect for suppressing the following corrosion, and the corrosion form was changed from general corrosion to localized one with increasing Al content in the alloys. In the simulated airborne sea salt corrosion test, mass loss of Mg alloys increased with the amount of the deposited salt and relative humidity. From the relationship between the water film thickness and Cl− ion concentration, it was also clarified that the corrosion rate of the Mg alloys mainly depended on the water film thickness.
