What Does Corrosion Product Mean?
Corrosion product is any substance which is formed as a result of corrosion. Corrosion products known as rust for iron and steel are formed and gradually grown on the surface of common steel and low-alloyed steel when they are exposed to humid air at room temperature.
Corrosion products often cover signs of corrosion, which make corrosion detection and early prevention difficult. Pitting corrosion can produce pits which are open (uncovered) or covered with a semi-permeable membrane of corrosion products.
Corrosionpedia Explains Corrosion Product
As the corrosion process progresses, corrosion products tend to build up in certain areas. These corrosion products have different elemental compositions than the original state. The new compositions exposed on the surface lead to changes in the anodic and cathodic areas. As the change in anodic and cathodic areas occurs, previously uncorroded areas of the metal can be attacked and begin to corrode. This accelerates the overall corrosion of the surface.
Corrosion products often cover pits. A small, narrow pit with minimal overall metal loss can lead to the failure of an entire engineering system. The corrosion products of steel are oxide particles and have a distinctive brown/red (rust) color. Just a small number of these particles can cause an uncoated steel surface to appear corroded.
Corrosion products are different for different metals. For example, green copper corrosion products, known as a patina, are often basic copper carbonate, basic copper sulfate or copper oxychlorides. Copper corrodes when exposed to carbon dioxide and water.
Silver tarnishes, which is a mild form of corrosion which ends when the product covers the surface of the metal. Silver tarnishing is another redox reaction in which silver is oxidized and hydrogen reduced to a gas. This is similar to the protective oxide layer which forms on aluminum.