Definition - What does Flash Corrosion mean?
Flash corrosion is the general and rapid corrosion that instantly occurs when metals are exposed to corrosive environments. This is a phenomenon associated with the rusting of a wet cast-iron pan that is left to dry by air.
Metals such as copper and aluminum can oxidize rapidly to form a layer for passivation. In this process, corrosion inhibitors are typically used to hinder formation of a passivation layer by keeping oxygen interaction on the surface.
Flash corrosion is also known as flash rusting or flashing.
Corrosionpedia explains Flash Corrosion
Flash corrosion is a severe problem for all water-borne-type coatings on steel. This type of corrosion occurs from the steel bleeding through the coat, leading to staining within hours after the coat has been applied. Flash corrosion occurs quickly, especially when thin water films reside on the steel surface, triggering the corrosive action. Most of the time, the corrosion products are soluble and capable of migrating within the coat and result in a stain.
This corrosion phenomenon occurs at the stages of paint application and drying. Thus, corrosion inhibitors or additives should be added during the drying stage to prevent flash corrosion from taking place. In fact, there are corrosion laboratory tests that can measure the effectiveness of corrosion inhibitors in terms of flash rusting. Such inhibitors are applied to the paint to prevent oxidation that is responsible for rusting. These tests are often carried out to assess the effectiveness of anti-flash corrosion additives in a particular type of coating. The duration of the test depends on the kind of coating and the results are usually expressed as the degree and rate of corrosion.
Such additives serve as one of the best ways to control flash corrosion. These chemicals are capable of insulating coating electrically or making the coating impermeable to fight electrochemical reactions. Therefore, the use of these chemicals can be very helpful, especially in water-borne systems as they can effectively combat flash rust and offer rust protection.