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Aluminum Plate Manufacturer Analysis of Corrosion Causes of Anti – rust aluminum plate

Edit:admin Date: 2017-02-23 14:44
Anti - rust aluminum plate because of its anti-rust anti-corrosion characteristics, is widely used, but there are many anti-rust aluminum plate surfaces will occur corrosion, in addition to product quality problems occur in some manufacturers, we also carried out in-depth study, anti-rust aluminum plate surface corrosion is due to crevice corrosion.
Firstly, anti - rust corrosion of aluminum surface corrosion is due to the crevice corrosion. The mechanism of crevice corrosion is the occurrence of redox reactions at the gaps.
The conditions of crevice corrosion are: the width of the gap is in the range of 0.025 ~ 0.1mm; the fluidity of the corrosive medium is poor; with electrode potential difference.

If the metal or alloy corrosion resistance depends on the oxide film or passivation film, particularly vulnerable to crevice corrosion, because this type of oxide film or passivation film is easy to be high concentrations of chloride or hydrogen ions damage, thereby accelerating the dissolution of metal speed. Because this batch of anti - rust aluminum plate is cut in the end of July and early August rainy season, high air humidity, anti - rust aluminum surface roughness is not high, in the surface it is likely to remain a lot of water vapor. In the process of cutting and other processing, surface adsorption of water vapor is not fully volatile, coupled with the accumulation after cutting together, between the board and the plate must exist 0.025 ~ 0.1mm gap, and one plate press other plate, the water vapor is difficult to volatilize. In this case, it is likely to produce crevice corrosion. Especially for aluminum depends on the passivation film Al2O3 to corrosion resistance of the metal, the corrosion products are mainly Al (OH) 3. Such corrosion is likely to occur in almost all corrosive media, including fresh water. If the medium contains chloride ions, corrosion is more sensitive.
Secondly, another reason for the surface corrosion of anti - rust aluminum plates is the occurrence of point corrosion. Aluminum can produce an amorphous oxide film with a thickness of about 1 nm in a dry atmosphere. Test results show that there are various ions on the corrosion products, such as Cl -, (OH) - and impurity Fe3 + plasma.
Thirdly, white spots are the product of the initial corrosion, and black spots are in the late product, so there are subtle differences in its elements. The late product relative to the initial product, its element composition is more complex, more impurity elements.
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