Surface treatment of aluminum alloy die castings

Surface treatment of aluminum alloy die castings

Aluminum alloy die castings have many advantages over other castings. For example, castings are exquisite, light in weight, and corrosion-resistant, so they are loved by many industries, especially in terms of automotive lightweight, aluminum alloy die-castings have been widely used in the automotive industry. After surface treatment, aluminum alloy die castings will be more perfect and more popular with consumers.

Anodizing is a surface treatment process for aluminum alloy die castings. Anodizing forms a corrosion-resistant and wear-resistant layer on the surface of aluminum alloy die castings by using a chemical solution. The anodizing process will also change the crystal structure of the surface of the material, which can change the color of the aluminum alloy die casting, so that the ordinary aluminum alloy die casting has a more vivid color.

At present, there are many choices of aluminum alloy anodizing colors, common ones are black, silver white, red, etc., and the finished products are very beautiful.

Powder coating is another surface treatment process for aluminum alloy die castings. Powder coating is sprayed on the surface of aluminum alloy parts, and under the action of static electricity, the powder will adhere to the surface of the parts to form a powder coating.

The spraying effect of powder coating is better than that of spray paint in terms of mechanical strength, adhesion, corrosion resistance, aging, etc., and the cost is also cheaper.

Electroplated coated aluminum alloy die castings can further protect or improve the availability of aluminum alloys in harsh or special environments. Electroplating is the process of electrolytically depositing a metal or alloy on the surface of a part to form a uniform, dense and cohesive metal layer. Aluminum alloys cannot be electroplated from conventional aqueous baths because it is too reactive a metal and almost all the electricity is used to electrolyze hydrogen from water instead of depositing aluminum. But electroplating aluminum is a special process, which must be done with special organic solvents, and can also be electroplated by ionic liquids.

Sandblasting is another surface treatment process for aluminum alloy die castings. Usually, a layer of fine sand is sprayed on the surface of aluminum alloy die castings to enhance the friction coefficient of the contact surface and also enhance the stability of the connection.

Baking paint is also a common surface treatment process for aluminum alloy die castings. The real paint baking process is a repeated process of aluminum alloy phosphating, spraying, then spraying, and baking. Therefore, the baking varnish coating is not only corrosion-resistant but also bright, wear-resistant, and not easy to fall off.

For electrophoresis, the work-piece is placed as an electrode in a conductive water-soluble or water-emulsified paint, and forms a circuit with another electrode in the paint. Under the action of an electric field, the coating solution has been dissociated into charged resin ions, the cations move to the cathode, and the anions move to the anode. These charged resin ions, together with the adsorbed pigment particles, electrophoresis to the surface of the work-piece to form a coating. This process is called electrophoresis.

The purpose of surface treatment of aluminum alloy die castings is to get better coatings to adapt to more use environments and more beautiful appearance!