Analysis of surface treatment methods of products after etching

After etching, the product is the original color of the metal, and many require subsequent surface coloring treatment: surface color whitening treatment; surface mirror bright treatment;  surface coloring treatment.

1. Surface whitening treatment: During the processing of precision etched products, black oxide skin is produced by rolling, tying, welding or artificial surface fire heating. This hard gray-black oxide scale is mainly composed of two EO4 components, NiCr2O4 and NiF. In the past, hydrofluoric acid and nitric acid were generally used for strong corrosion removal. However, this method has high cost, pollutes the environment, is harmful to human body, and is highly corrosive, and is gradually eliminated. At present, there are two main methods of oxide skin treatment:

(1) Sandblasting (pellet) method: The method of spraying micro glass beads is mainly used to remove the black oxide scale on the surface.

(2) Chemical method: Use a non-polluting pickling passivation paste and a non-toxic cleaning solution with inorganic additives at room temperature for dipping. So as to achieve the purpose of whitening the original color of precision etching products. After processing, it basically looks like a dull color. This method is more suitable for large, complex products.

2. Mirror bright treatment method on the surface of precision etched products: According to the complexity of precision etched products and different user requirements, mechanical polishing, chemical polishing, electrochemical polishing and other methods can be used to achieve mirror gloss.

3. Surface coloring treatment: The coloring of precision etched products not only imparts various colors to precision etched products, but also increases the variety of precision etched products, but also improves product wear resistance and corrosion resistance. The coloring methods of precision etching products are as follows:

(1)chemical oxidation coloring method; 316 stainless steel plate

(2) Electrochemical oxidation coloring method;

(3) Ion deposition oxide coloring method;

(4)high temperature oxidation coloring method;

(5) Gas-phase cracking coloring method.

A brief overview of the various methods is as follows:

(1)Chemical oxidation coloring method: It is the color of the film formed by chemical oxidation in a specific solution, including dichromate method, mixed sodium salt method, vulcanization method, acid oxidation method and alkaline oxidation method. Generally, "INCO" (INCO) is used more, but if you want to ensure the same color and luster of a batch of products, you must use a reference electrode to control.

(2) Electrochemical coloring method: It is the color of the film formed by electrochemical oxidation in a specific solution.

(3) Ion deposition oxide coloring method chemical method: It is to place the precision etched workpiece in a vacuum coating machine for vacuum evaporation plating. For example: titanium-plated watch cases and watch straps are generally golden yellow. This method is suitable for high-volume product processing. Because of the large investment and high cost, small batch products are not cost-effective.

(4)High temperature oxidation coloring method: In a specific molten salt, the workpiece is immersed in a certain process parameter, so that the workpiece forms a certain thickness of oxide film, and presents various colors.

(5) Gas-phase cracking coloring method: It is more complicated and less used in industry.