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Shanghai aluminum hard anodic oxidation process characteristics | | industry information
Shanghai aluminum hard anodic oxidation process characteristics of hard anodic oxidation is also called the thick layer of anodic oxidation. It is a new technology developed in the 50 s, the thickness of the oxide film is up to 250 um, in Shanghai, pure aluminum oxide film on the microhardness of up to 1500 hv, in Shanghai on aluminum alloy can reach 300 ~ 500 hv. Because of the hard anodic oxidation have many unique physical and chemical properties, thus has been widely used. Hard anodic oxidation film, both high hardness and wear resistance, and good insulation and insulation. Thickness is 100 um oxide film, can withstand voltage of 2000 ~ 2500 v. In the Marine and general industrial atmosphere all have good corrosion resistance. Making a lot of hard anodic oxidation film method, such as sulfuric acid, oxalic acid and organic acid, and so on. The most widely with sulfuric acid method, among them, the following by sulfuric acid electroplating factory in shenzhen to introduce the legal process of hard anodic oxidation. Hard anodic oxidation process and the mechanism of the common mechanism of anodic oxidation film, is a membrane process of electrochemical generation and chemical dissolve two mutual transformation result. However, in order to get high hardness, coating thickness of oxide film, in the process of anodic oxidation, must reduce the bath temperature, in order to reduce the dissolution rate of oxidation film. Due to the hard anodized film thickness, density, high resistance, influence of anodic oxidation process. In order to make the normal oxidation, and meet the requirements of thickness, is bound to increase the cell voltage to overcome the influence of resistance, keep the anode current. Due to the voltage, electric current is too large, will produce a lot of heat, cause the parts near solution temperature, accelerate oxidation film dissolve. In order to eliminate the effects, need to adopt artificial forced cooling refrigeration equipment, strong stirring and compressed air purification, take away the heat around the parts. Hard anodic oxidation commonly use - at low temperature 5 ~ + 9 ℃, so the electrolyte effect on oxide film of dissolved slowly. And because of using high voltage ( 60 ~ 120 v) And the larger current density ( 2. 5 ~ 4 a / dm2) , which makes the balance of time delay, so can get thick and compact oxidation film membrane layer.