The anodic treatment of aluminum alloy die casting is explained.
Most chooses al-si alloy, aluminum alloy die casting aluminum silicon alloy containing primary silicon and eutectic silicon, silicon cannot be when anodized oxidation, as long as the aluminum substrate by oxidation, so after anodized aluminum silicon alloy castings, porous loose shape, appearance is not maintained, if the request is not high quality of appearance, also can choose anodized appearance treatment.
Before selective oxidation technology, deal with aluminum or aluminum alloy materials, because of data quality, contains ingredients, will directly affect the quality of the aluminum anodic oxidation after. For this point, comrade hong jiude and fan ji have made a special discussion (see "electroplating and finishing", no.2, P.27, 1982). For example, the appearance of aluminum material, such as bubble, scratch, peeling, rough, etc., after anodizing, the defect will still be revealed. And the composition of the alloy has a direct effect on the appearance and appearance of the anodic oxidation. For example, aluminum alloy with 1 ~ 2% manganese, after oxidation, is brown and blue. With the addition of manganese content in aluminum, the appearance of oxygen after oxidation is transformed from brown and blue to dark brown. Aluminum alloys containing 0.6 ~ 1.5% of silicon are grey and gray, with silica content of 3 ~ 6%. The milky color of zinc, containing chromium yellow to gray color, and nickel in a yellowish color. In general, as long as the containing magnesium and titanium content is greater than 5% of the aluminum containing gold, after oxidation, it will be able to obtain a colorless, bright and bright appearance.
Electrochemical oxidation of metal or alloy. The metal or alloy parts as anode, with electrolytic method makes its appearance constitute the oxide film. Metal oxide film has changed the appearance and function condition,
Progress such as appearance, color, corrosion resistance, and enhance the wear resistance and hardness, maintain metal appearance, etc., for example, aluminum anodic oxidation, the aluminum and its alloys in corresponding electrolyte (such as sulfuric acid, chromic acid, oxalic acid, etc.) as the anode, under certain conditions and impressed current, electrolytic. Anode aluminum or its alloy oxidation, constitute a thin layer of alumina on the surface, the thickness is 5 ~ 20 microns, hard anodic oxidation film can reach
60 to 200 microns. After anodic oxidation of aluminum or its alloy, improved the hardness and wear resistance, can reach 250 ~ 500 kg per square millimeter, good heat resistance, hard anodic oxidation film melting point as high as 2320 k, excellent insulation, resistance to breakdown voltage of 2000 v, enhance the function of corrosion, hitches in omega = 0.03 NaCl salt fog corrosion thousands of hours. Oxide film has such a large number of microporous thin layer, can adsorption various lubricant, or other appropriate manufacturing engine cylinder wear parts; Membrane pores adsorption ability can be colored into all sorts of beautiful beautiful colour. Non-ferrous metal or its alloy (such as aluminum, magnesium and its alloys, etc.) can be anodic oxidation treatment, this method is widely used in machinery parts, auto parts, precision instruments and radio devices, daily provisions, building decoration etc.
Remedy: in the practical technology for the anodic oxidation of aluminum alloy, is more, can be used in normal days, thought that the characteristics of this technology, the maintenance of hard layer in the aluminum appearance, can be used to produce kitchen utensils and appliances and other daily provisions. But forging aluminum anodic oxidation owe good, appearance is not sleek, also can only be black. Aluminum alloy profile is better. Login details: www.harrellland.net