With the development of science and technology, people put forward a variety of new requirements for the surface performance and appearance of CNC machining aluminum alloy shell. For example, when the product is widely used for electroplating, people are more and more disgusted with the luminous electroplating luster, and turn to love the color of fog, as simple as satin color. Therefore, electroplating alloy was developed. This paper briefly introduces several decorative electroplating alloys used in product finishes.
1. CNC machining aluminum alloy shell – electroplated tin – cobalt alloy
The tin-cobalt alloy electroplating is close to the color of cobalt electroplating, but it is softer and more popular among people. At present, it is mostly used to replace chromium in foreign countries. Cobalt plating is not easy to roll plating, and tin – cobalt alloy plating is suitable for small parts roll plating. In addition, the anodized tin-cobalt alloy has excellent ability of uniform plating and rolling plating, so it is suitable for complex shape workpiece. If the bottom layer is coated with nickel, the corrosion resistance is no less than that of chromium. In order to prevent surface discoloration, the method of impregnating chromate is used to treat it, which can also improve its corrosion resistance.
Its appearance has a light rose color, makes people feel very good, and has excellent corrosion resistance. If on the shiny substrate or on the bright nickel electroplating, then apply tin-nickel alloy plating, can obtain a good gloss surface. If the luster of the surface (pear grain) on the plating, can appear on the original situation. The plating ability of electrodeposits is very good, almost no leveling, so it is suitable for electroplating of very thin lines and rotating processed products.
2.CNC machining of aluminum alloy – plating copper – tin alloy
Low tin bronze coating of aluminum alloy shell is pink or gold in color, fine crystal, it has a high corrosion resistance and good optical properties, it is often used as a protective – decorative nickel substrate, used in light industry, handicraft industry, mechanical instrument industry and other industries. Medium tin bronze coating is golden in color and corrosion resistance. Mainly used for decorative chrome plating of the bottom layer.
The hardness and stability of aluminum alloy in air are higher than that of tin bronze coating. However, due to the higher tin content of the coating, the bottom layer of the decorative coating for protection is easy to flower after chromium, which is the weakness of the middle tin bronze coating.High tin bronze coating with beautiful silver-white luster and good rotative property, high hardness and wear resistance, used in industrial design to replace silver or chromium as reflective instruments, instruments, daily goods, such as protection – decorative surface coating.