The role of anodic oxidation treatment for aluminium and aluminium alloy plates

The role of anodic oxidation treatment for aluminium and aluminium alloy plates

Aluminium and its alloys will oxidise in the air. The naturally formed oxide film on the surface of aluminium is amorphous, it will make the surface of aluminium metal lose its original lustre, although this natural oxide film will make the surface of aluminium metal slightly passivated, but it is very thin, about 4-5nm, and with large porosity and poor mechanical properties, it cannot effectively prevent further corrosion of aluminium metal by various media in the atmosphere. As aluminium sheets and their alloy products have many characteristics after anodising, the aluminium anodising process is widely used in the surface treatment of aluminium products. The applications in industry can be broadly classified as follows.

(1) Prevention of corrosion of aluminium alloy sheet products

As the film layer obtained by anodising is properly closed and treated, it has good stability in the atmosphere. Whether the oxide film is obtained from sulphuric acid solution, oxalic acid solution or chromic acid solution in the normal process, its corrosion resistance is very good, such as the daily use of aluminium pots and pans, washing machine lining, etc.. The chromic acid oxidation method is particularly suitable for aluminium welded and riveted parts.

(2) Protection - decoration

In the acquisition of high transparency of the oxide film, aluminum plate oxide film has the characteristics of a variety of organic dyes or inorganic pigments can be adsorbed, the oxide film can be obtained on a variety of bright and vivid colours and patterns, coupled with the emergence of many new processes in recent years such as an oxidation of multiple coloring, gift patterns, wood grain patterns, oxidation offset transfer printing, porcelain oxidation, etc., so that the appearance of aluminum more beautiful and pleasing, this layer of colour film is both a decorative layer and is an anti-corrosion layer, such as lighters, gold pens and crafts.

Of course, in addition to these two benefits there are many other advantages of anodising, such as making aluminium alloy sheets more wear resistant and insulating them from electrical conductivity. If you need aluminium alloy sheets with these features, please contact us at Haomei Aluminium Co.