Analysis of product surface treatment methods after etching processing

After etching, the products are metal color, and many of them need subsequent surface coloring treatment: a surface color whitening treatment; b surface mirror bright treatment; c Surface coloring treatment.

1. Surface color whitening treatment: precision etching products in the process of processing, after rolling plate, tie edge, welding or after artificial surface fire roasting heating treatment, black oxide skin. This hard gray black oxide skin is mainly NiCr2O4 and NiF two EO4 components, previously generally using hydrofluoric acid and nitric acid to remove strong corrosion methods. However, this method is costly, polluting the environment, harmful to human health, corrosive, and gradually phased out. At present, there are two main treatment methods for oxide skin:

(1) sand blasting (shot) method: mainly the method of spraying micro glass beads to remove the black oxide skin on the surface.

Chemical method: The use of a pollution-free pickling passivation paste and room temperature non-toxic cleaning liquid with inorganic additives for immersion. So as to achieve the whitening of precision etching products. It's basically a matte color. This method is suitable for large and complex products.

2. Processing method of mirror brightness on the surface of precision etching products: according to the complexity of precision etching products and different user requirements, mechanical polishing, chemical polishing, electrochemical polishing and other methods can be used to achieve mirror luster.

3. Surface coloring treatment: precision etching products coloring not only gives precision etching products a variety of colors, increase the color of precision etching products, but also improve the wear resistance and corrosion resistance of products. Precision etching product coloring methods are as follows:

(1) Chemical oxidation coloring method

(2) Electrochemical oxidation coloring method;

(3) Ion deposition oxide coloring method;

(4) High temperature oxidation coloring method;

(5) Gas phase cracking coloring method.

The various methods are summarized as follows:

(1) Chemical oxidation coloring method: that is, in a specific solution, through chemical oxidation to form the color of the film, there are dichromate method, mixed sodium salt method, vulcanization method, acid oxidation method and basic oxidation method. Generally "INCO" (INCO) is used more, but to ensure that a batch of products color uniformity, must be controlled with reference electrodes.

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

(3) Chemical method of ion deposition oxide coloring method: the precision etching workpiece is placed in the vacuum coating machine for vacuum evaporation plating. For example: titanium plated watch case, watch belt, is generally golden. This method is suitable for large volume product processing. Because of the large investment and high cost, small batch products are not cost-effective.

(4) High temperature oxidation coloring method: is in a specific molten salt, immersed in the workpiece to maintain a certain process parameters, so that the workpiece form a certain thickness of oxide film, and show a variety of different colors and colors.

(5) Gas phase cracking coloring method: more complex, less used in industry.