Brief description of common types of corrosion of industrial aluminum profiles

In general, the corrosion type of industrial aluminum aluminum can be divided into: point corrosion, galvanic corrosion, crevice corrosion, intergranular corrosion, and filament corrosion. The following briefly describes these types of corrosion.

 

A point corrosion corrosion, also known as hole corrosion, is a type of extremely localized corrosion pattern in the needle tip, dot, and hole. Industrial aluminum profiles undergo pitting corrosion in atmospheric, freshwater, and neutral aqueous solutions. Severe can also lead to perforation, but the corrosion holes may eventually stop developing and the amount of corrosion remains at a limit. Pit corrosion is a unique form of anode reaction and is an autocatalytic process.

 

II. Galvanic corrosion Galvanic corrosion is also a characteristic corrosion pattern of industrial aluminum profiles. The natural potential of industrial aluminum profiles is very negative. When industrial aluminum profiles are in contact with other metals, industrial aluminum profiles are always at the anode, causing corrosion acceleration. . Galvanic corrosion, also called bimetallic corrosion, is determined by the relative position of two metal potential sequences.

 

3. Crevice Corrosion Crevice corrosion is the result of differential air-charged batteries, which leads to accelerated corrosion within the gaps of industrial aluminum profiles, with no effect outside the crevice. Crevice corrosion has little to do with the type of alloy. Even very corrosion resistant alloys can produce crevice corrosion. In recent years, the mechanism of crevice corrosion has been further studied. The acid environment at the top of the gap is the driving force of corrosion.

 

IV. Intergranular corrosion Intergranular corrosion refers to the fact that pure aluminum does not produce intergranular corrosion. Intergranular corrosion is related to improper heat treatment. Alloying elements or intermetallic compounds precipitate along the grain boundaries and form an anodic corrosion with respect to grains. The battery causes accelerated intergranular corrosion.

 

5. Filament corrosion Filament corrosion is an under-layer corrosion of industrial aluminum profiles. It develops in the form of worms under the film. This film can make the paint film, and it can also make other layers, generally does not occur under the anodized film.