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2023
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Types and characteristics of aluminum alloy corrosion in commonly used industrial aluminum profiles
Generally speaking, the basic types of industrial aluminum profiles and aluminum alloy corrosion: pitting corrosion, galvanic corrosion crevice corrosion, intergranular corrosion, stress corrosion, exfoliation corrosion, fatigue corrosion, filiform corrosion, etc., here, only the concentrated aluminum Common corrosion phenomena in the production and use of construction industrial aluminum profiles.
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Generally speaking, the basic types of industrial aluminum profiles and aluminum alloy corrosion: pitting corrosion, galvanic corrosion crevice corrosion, intergranular corrosion, stress corrosion, exfoliation corrosion, fatigue corrosion, filiform corrosion, etc., here, only the concentrated aluminum Common corrosion phenomena in the production and use of construction industrial aluminum profiles.
Pitting corrosion, also known as pitting corrosion, is an extremely partial corrosion pattern in the form of needlepoints, points, and holes on metals. Pitting corrosion is a common form of anodic reaction and is an autocatalytic process. Aluminum will undergo pitting corrosion in the atmosphere, fresh water, or neutral aqueous solution, and severe perforation may occur, but the corrosion holes may eventually stop developing, and the corrosion amount remains at a limit value. Pitting corrosion is related to the medium alloy to an extreme extent, such as chloride ion, fluoride ion, etc. There must also be substances that promote the cathode reaction, such as dissolved oxygen in aqueous solution, copper ions, etc. From the perspective of industrial aluminum alloys, high-purity aluminum is generally difficult to cause pitting corrosion, and copper-containing aluminum alloys have obvious pitting corrosion.
Galvanic corrosion is also a characteristic corrosion form of aluminum. The natural potential of aluminum is very negative. When aluminum is in contact with other metals, aluminum is always at the anode to accelerate its corrosion. Galvanic corrosion is also known as bimetallic corrosion, and the severity of the corrosion is determined by the relative orientation of the two metals in the potential series. The larger their potential difference is, the more serious the galvanic corrosion will be. Almost all aluminum alloys cannot prevent galvanic corrosion.
Crevice corrosion, there are gaps when the industrial aluminum profile aluminum itself or the surface of aluminum and other materials are in contact. Due to the different effects of inflatable batteries, the corrosion inside the crevice is accelerated, but there is no effect outside the crevice. Crevice corrosion has little to do with the type of alloy, and crevice corrosion can occur even in very corrosion-resistant alloys. In recent years, the mechanism of crevice corrosion has been further studied, and the acidic environment at the top of the crevice is the driving force for corrosion. Corrosion under deposits is a form of crevice corrosion.
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