Commonly used stainless steel surface treatment technology has the following treatment methods: ① Surface Color whitening treatment, ② surface mirror bright treatment, ③ surface coloring treatment. 1.2.1 Surface Color Whitening treatment: Stainless steel in the processing process, after the coil, Zaben, welding or through the artificial surface of the fire roasting heating treatment, resulting in black oxide skin. This hard gray-black oxidized skin is mainly NiCr2O4 and NiF two kinds of EO4 components, before the general use of hydrofluoric acid and nitric acid for strong corrosion methods to remove. But this method has a big cost, pollutes the environment, is harmful to the human body, the corrosive is larger, gradually is eliminated.
There are two main types of oxidation skin treatment methods:
⑴ Sand Blasting (pills) method: mainly the use of micro-glass beads to remove the surface of the black oxide skin. ⑵ Chemical method: The use of a pollution-free pickling passivation cream and non-toxic cleaning liquid with inorganic additives at room temperature for dipping. In order to achieve stainless steel color whitening treatment purposes. After treatment, it basically looks like a light-free color.
This method is more suitable for large and complex products. 1.2.2 Stainless steel surface mirror Bright treatment method: According to the complexity of stainless steel products and user requirements, can be used mechanical polishing, chemical polishing, electrochemical polishing and other methods to achieve mirror luster.
The advantages and disadvantages of these three methods are as follows:
1.2.3 Surface Coloring Treatment: Stainless steel coloring not only gives stainless steel products a variety of colors, increase the color variety of products, but also improve product wear resistance and corrosion resistance.
There are several ways to color stainless steel:
⑴ chemical oxidation coloring method;
⑵ electrochemical oxidation coloring method;
⑶ ion deposition oxide coloring method;
⑷ high temperature oxidation coloring method;
⑸ gas phase cracking coloring method.
The simple overview of the various methods is as follows: ⑴ Chemical Oxidation Coloring method: is in a specific solution, through chemical oxidation to form the color of the membrane, there is dichromate method, mixed sodium salt method, vulcanization method, acid oxidation method and alkaline oxidation method.
Generally "Yin Ke method " (INCO) use more, but to ensure that a batch of products color consistent, must be controlled with reference electrodes.
⑵ Electrochemical Coloring method: is in a specific solution, through electrochemical oxidation to form the color of the membrane. ⑶ ion deposition oxide Coloring Method Chemical method: Is the stainless steel workpiece placed in the vacuum coating machine for vacuum evaporation plating. For example: Titanium plated gold watch shell, watch strap, generally golden yellow. This method is suitable for high-volume product processing.
Because of the large investment, high cost, small batches of products are not cost-effective.
⑷ 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 to form a certain thickness of the oxide film, and presents a variety of different colors. ⑸ gas phase cracking coloring method: more complex, less used in industry.