aluminum Hard anodizing

Hard anodizing is the full name of hard anodizing. The thickness of hard anodic oxide film is generally required to be 25-150um. The thickness of most hard anodic oxide films is 50-80um. The thickness of hard anodic oxide film with film thickness less than 25um is used for parts used in tooth keys, spirals and other occasions. The thickness of anodic oxide film for wear resistance or insulation is about 50um. Under some special process conditions, it is required to produce hard anodic oxide film with thickness of more than 125um, However, it must be noted that the thicker the anodic oxide film, the lower the microhardness of the outer layer and the increase of the surface roughness of the film. The bath solution for hard anodizing is generally sulfuric acid solution and sulfuric acid added organic acids, such as oxalic acid, aminosulfonic acid, etc. In addition, the hard anodizing treatment can be realized by reducing the anodizing temperature or reducing the sulfuric acid concentration. For deformed aluminum alloys with copper content greater than 5% or silicon content greater than 8%, or die-casting aluminum alloys with high silicon, some special measures of anodizing may also be considered. For example, for 2XXX series aluminum alloy, 385g / L sulfuric acid and 15g / L oxalic acid can be used as electrolytic cell solution to avoid burning of aluminum alloy during anodizing, and the current density should also be increased to more than 2.5a/dm.