Hard aluminum anodic oxide film characteristics
hard aluminum anodized characteristics with the continuous development of aluminum products processing industry, hard anodized aluminum is more and more widely used in the industry of aluminum anodic oxidation and chemical oxidation method, the aluminium and aluminium alloy surface generates a layer of oxide film, to achieve the purpose of protection a decoration. Aluminium and aluminium alloy in the atmosphere can naturally formed a layer of oxide film, but the thin membrane ( 40 - 50) And porous for amorphous, inhomogeneous and discontinuous film layer, not as a decorative reliable protective film layer. A, the oxide film obtained with chemical oxidation treatment, the thickness is commonly 0. 3 ~ 4 um, soft, abrasion resistance and corrosion resistance were lower than that of aluminum anode oxide film. So, except with special purpose, rarely used alone. But it has good adsorption ability, to paint on the surface, can effectively improve the corrosion resistance of aluminum products and decorative. Second, the oxide film obtained with aluminum anodic oxidation treatment, the thickness is in commonly - 5 20 v m, hard aluminum anodized film thickness can reach 60 2500m。 The film also has the features: ( 1) Have good insulation performance. Aluminium and aluminium alloy aluminum anodic oxide film, don't have the conductive properties of metal, and become a good insulating material. （ 2) Have strong ability of adsorption. Aluminium and aluminium alloy aluminum anodic oxide film of porous structure, has a strong adsorption capacity, so give hole filling all kinds of aluminum pigments, lubricants, resin can be further improve protection, insulation, wear resistance of aluminum products and decorative performance. （ 3) Adiabatic thermal performance is strong. This is because the coefficient of thermal conductivity of aluminum anode oxide film is much lower than the pure aluminum? Aluminum anodic oxidation film can heat resistance around 1500 ℃, and pure aluminium can only 660 ℃. Well the place on put together is narrated, aluminum and aluminum alloy by chemical oxidation treatment, especially after aluminum anodic oxidation treatment, formed on the surface of oxide film has good protection features such as a decoration. As a result, they are widely used in aviation, electrical, electronic, machinery and light industry, etc. （ 4) Hardness is higher. Pure aluminium oxide film hardness is higher than the hardness of aluminum oxide film. Usually, its size and the hardness of aluminum alloy components, aluminum anodic oxidation technology conditions of electrolyte. Aluminum anodic oxide film is not only high hardness and good abrasion resistance. Especially in the surface layer of porous oxide film has the ability of adsorption lubricant, also can further improve the surface wear resistance. （ 5) Have higher corrosion resistance. This is because the aluminum anode oxide film has high chemical stability. After the test, the aluminum anodic oxide film of pure aluminum than the aluminum anodic oxide film of aluminum alloy corrosion resistance. This is due to the alloy elements inclusion or forming metal compounds can't be oxidation or be dissolved, and make the space discrete or produce oxide film, which greatly reduced the corrosion resistance of oxide film. So, generally after the aluminum anodic oxidation film must be closed processing, to improve its corrosion resistance.