The advantages of anodising aluminium alloy sheets and plates

The advantages of anodising aluminium alloy sheets and plates

With the development of modern industry, the application of light metal materials has become increasingly widespread. With a series of advantages such as low density, strong electrical and thermal conductivity, excellent mechanical properties and good processability, aluminium alloy sheets and plates have been widely used in various sectors of the national economy.

In the construction field, for example, 98% of the high-rise buildings in Japan use aluminium alloy for doors, windows and wall decoration. Compared with ordinary wooden doors and windows, steel doors and windows, aluminium alloy panels and aluminium windows have the characteristics of light quality, material saving, beautiful, corrosion resistance and easy maintenance. Although the cost is 3~4 times higher than ordinary wooden doors and windows, they have a broad development prospect because of low long-term maintenance cost. In the atmosphere, aluminium and aluminium alloy surface and oxygen can form a layer of oxide film, but the film is thin (3 × 10-3 ~5 × 10-3μm) and loose porous, amorphous, uneven and discontinuous film layer, can not be used as a reliable protective - decorative film. At present, aluminium anodising or chemical oxidation is widely used in industry to produce an oxide film on the surface of aluminium alloy sheets and plates for protective and decorative purposes.

The aluminium alloy and aluminium plate oxide film obtained by chemical colour oxidation treatment is generally 0.3~4μm thick, with soft texture, wear resistance and corrosion resistance lower than that of anodic oxide film. The thickness of the oxide film obtained by anodic oxidation is generally 5~20μm, while the thickness of the hard anodic oxide film can be 60~250μm, which is firmly bonded with the base metal and has high corrosion resistance, wear resistance and hardness. The porous oxide film has a strong adsorption capacity and is easy to colour with organic dyes, and also has good insulating properties and strong adiabatic and thermal resistance.