Visual degradation of Zinc-surfaces in salt-spray tests: Black spots and White haze

摘要

Exposing samples to a neutral salt-spray in a corrosion climate chamber determines the corrosion resistance of passivated zinc or zinc alloy coatings. Clear surface finishes tend to produce black spots before the formation of voluminous white corrosion products, while black or dark finishes tend to form a white haze. This paper will try to reveal the mechanism of this corrosion mechanism that on many occasions confuses the outcome of corrosion testing. The black spots and white haze phenomena seem to be closely related.