Commonly Used Aluminum Alloys and Oxidation
Series 1 aluminum alloy, Pure Aluminum ".
Pure aluminum is generally not used for hard anodizing. In bright anodizing, after brightening
treatment and anodizing, the higher the purity of aluminum, the better the reflectiveness of the
light mirror surface. the smaller the so-called "loss of light" after anodizing. 1099 aluminum (aluminum content is not less than 99.99%), with the best light reflectance. In general, industrial applications, 1098 aluminum (aluminum content of not less than 99.98%) has been used for brightness and formability as the main purpose without considering the mechanical properties of the occasion. 1100 aluminum after mechanical polishing or chemical polishing, the reflectivity of incandescent light can reach 86%. In the protective anodizing treatment, the higher the purity of aluminum, the corrosion resistance of the anodized film also significantly improve.
Series 2 aluminum alloy, Al-Cu-Mg alloy.
The deformed aluminum alloy can be strengthened by heat treatment. The material forms are
plate, tube, rod, mold and wire. The main alloying elements of this series of alloys are copper and
magnesium, and contain a small amount of Mn, Cr and Zr. The copper content 2 series is 2% to 10%, of which the strength is highest when the copper content is 4% to 6%. 2 series is generally not suitable for bright anodizing. Its mechanical properties are relatively high, mainly used in
aerospace industry.
The Al-Cu intermetallic compound in the alloy is easily dissolved during anodizing, it is difficult to generate a dense anodizing film, and its film formation rate is also relatively low. In the protective anodizing, the corrosion resistance of the anodized film is worse than that of pure aluminum, so the anodizing temperature should be appropriately reduced, and the anodizing time of the same film thickness should be extended by 1/3.
hard anodizing of 2 series of aluminum alloy is more difficult, which need to develop special technology. It is suggested use pulse power supply or other special power supply, voltage rise should not be too fast, should control step stage rise.
Series 3 aluminum alloy, Al-Mn alloy.
3 series heat treatment cannot strengthen the deformation of aluminum alloy. Although there
are extrusion materials, but is mainly the plate, 3004 aluminum alloy is the largest production of
sheet aluminum alloy. Manganese can not only improve the mechanical properties of aluminum
alloy, but also avoid reducing the corrosion resistance of anodic oxide film. Because there are
Al-Mn intermetallic compound particles in aluminum, the anodic oxide film is light gray or grayish
brown. In bright anodizing, with the increase of the thickness of the anodized film, the brightness of surface decreases significantly, so the film thickness is generally controlled below 5um. The
hard anodizing of 3 series aluminum alloy is less, and the anodized film produced is darker color.
Pure aluminum is generally not used for hard anodizing. In bright anodizing, after brightening
treatment and anodizing, the higher the purity of aluminum, the better the reflectiveness of the
light mirror surface. the smaller the so-called "loss of light" after anodizing. 1099 aluminum (aluminum content is not less than 99.99%), with the best light reflectance. In general, industrial applications, 1098 aluminum (aluminum content of not less than 99.98%) has been used for brightness and formability as the main purpose without considering the mechanical properties of the occasion. 1100 aluminum after mechanical polishing or chemical polishing, the reflectivity of incandescent light can reach 86%. In the protective anodizing treatment, the higher the purity of aluminum, the corrosion resistance of the anodized film also significantly improve.
Series 2 aluminum alloy, Al-Cu-Mg alloy.
The deformed aluminum alloy can be strengthened by heat treatment. The material forms are
plate, tube, rod, mold and wire. The main alloying elements of this series of alloys are copper and
magnesium, and contain a small amount of Mn, Cr and Zr. The copper content 2 series is 2% to 10%, of which the strength is highest when the copper content is 4% to 6%. 2 series is generally not suitable for bright anodizing. Its mechanical properties are relatively high, mainly used in
aerospace industry.
The Al-Cu intermetallic compound in the alloy is easily dissolved during anodizing, it is difficult to generate a dense anodizing film, and its film formation rate is also relatively low. In the protective anodizing, the corrosion resistance of the anodized film is worse than that of pure aluminum, so the anodizing temperature should be appropriately reduced, and the anodizing time of the same film thickness should be extended by 1/3.
hard anodizing of 2 series of aluminum alloy is more difficult, which need to develop special technology. It is suggested use pulse power supply or other special power supply, voltage rise should not be too fast, should control step stage rise.
Series 3 aluminum alloy, Al-Mn alloy.
3 series heat treatment cannot strengthen the deformation of aluminum alloy. Although there
are extrusion materials, but is mainly the plate, 3004 aluminum alloy is the largest production of
sheet aluminum alloy. Manganese can not only improve the mechanical properties of aluminum
alloy, but also avoid reducing the corrosion resistance of anodic oxide film. Because there are
Al-Mn intermetallic compound particles in aluminum, the anodic oxide film is light gray or grayish
brown. In bright anodizing, with the increase of the thickness of the anodized film, the brightness of surface decreases significantly, so the film thickness is generally controlled below 5um. The
hard anodizing of 3 series aluminum alloy is less, and the anodized film produced is darker color.