The prototype made of aluminum alloy material generally needs later surface treatment. These surface treatment processes include sand blasting, coloring, electrochemical oxidation, spraying, chemical polishing and passivation .Let's take a look at how these processes work and what their effects are.
1.Chemical oxidation
Aluminum and aluminum alloy prototype chemical oxidation treatment equipment is simple, easy to operate, high production efficiency, does not consume electricity, wide range of application, not limited by the size and shape of parts. The process of chemical oxidation of aluminum and its alloys can be divided into basic oxidation process and acid oxidation process. The film can be divided into oxide film, phosphate film, chromate film, chromate-phosphate film. The oxide film is relatively thin, about 0.5 ~ 4 micron thick, porous, soft, with good adsorption, can be used as the bottom layer of organic coating, but its wear resistance and corrosion resistance are not as good as the anodic oxide film; The process of chemical oxidation of aluminum and its alloys can be divided into basic oxidation process and acid oxidation process. The film can be divided into oxide film, phosphate film, chromate film, chromate-phosphate film.
2. The sandblasting
Sandblasting is the main role of surface cleaning, in the coating (spray paint or spray) before the sandblasting of aluminum alloy prototype can increase the surface roughness, the adhesion of aluminum alloy prototype has a certain contribution to improve, but the contribution is limited, not as chemical coating before treatment.
3. Tinted
The tinted methods of aluminum alloy prototype include electrolytic coloring, chemical dyeing and natural coloring (overall coloring).In the electrolytic coloring process of aluminum alloy prototype, the metal (or oxide) particles generated by electrochemical reduction are deposited at the bottom of the oxidation film pores, and the color is not the color of the sediment, but the result of the scattering of the deposited particles to human light. Chemical dyeing is the adsorption of inorganic or organic dyes on the top of the oxide membrane pores, color is the color of the dye itself. Electrolytic coloring has low cost and good weather resistance. Chemical staining is colorful but easy to discolor when used outdoors.
4. Electrochemical oxidation
Aluminum and aluminum alloy chemical oxidation treatment equipment is simple, easy to operate, high production efficiency, does not consume electricity, wide range of application, not limited by the size and shape of aluminum alloy prototype parts. The thickness of the oxide film is about 5 ~ 20 microns (the thickness of the hard anodic oxide film is up to 60 ~ 200 microns), with high hardness, good heat resistance and insulation, higher corrosion resistance than the chemical oxide film, porous, with good adsorption ability.
5. Spraying
Used for the exterior protection and decoration of aluminum alloy hand plate, usually on the basis of oxidation.Aluminum pieces before coating should be pretreated to make the coating and the product bond firmly, there are generally three methods: phosphating (phosphate method), chromium (chrome-free chromium), chemical oxidation.
6.Chemical polishing
Chemical polishing is a chemical processing method that USES the selective self-dissolution of aluminum and aluminum alloy in acidic or alkaline electrolyte solution to level and polish the annual surface to reduce its surface roughness and PH. This polishing method has the advantages of simple equipment, no power supply, not limited by the size of aluminum alloy hand plate parts, high polishing speed and low processing cost. The purity of aluminum and aluminum alloy has a great influence on the quality of chemical polishing.
7, Passivation
A reactive metal or alloy in which the chemical activity is greatly reduced and becomes a noble metal state phenomenon called passivation. The surface passivation of aluminum alloy hand plate is a method to change the metal surface into a state which is not easy to be oxidized and to delay the corrosion speed of the metal. If the corrosion product generated by the metal due to the action of the medium has a dense structure, forming a layer of thin film (often invisible), tightly covering the surface of the metal, it will change the surface state of the metal, making the metal electrode potential jump greatly in the positive direction, and become a blunt state of corrosion resistance. Such as Fe Fe++ when the standard potential is -0.44v, passivation jump to + 0.5-1v, and shows the corrosion resistance of precious metals, this layer of film is called passivation film.
The above seven methods are the commonly used surface treatment technology of aluminum alloy hand plate. However, Duochuang prototype will always pay attention to the latest technical trend of the industry, timely learn and adopt the latest surface treatment technology of prototype, so as to bring better appearance and functional experience for customers' prototype model.
