Briefly analyze the blackening treatment process of metal surface

Metal surface blackening treatment is a chemical surface treatment process, the main principle is to form an oxide film on the metal surface to isolate the air and achieve the purpose of rust prevention. This treatment can eliminate reflections, and is often used in military knives and other occasions where reflections need to be eliminated. Blackening methods include alkaline oxidation, which is carried out in a solution containing oxidizing agent and sodium hydroxide, and acid oxidation, which uses a working solution containing phosphoric acid and oxidant. The alkaline oxidation method yields an oxide film thickness of 0.8 to 1.5 microns, while the acidic oxidation method is carried out at room temperature and is called cold hair blue, and its oxide film thickness can reach 3 microns. Although the film strength and corrosion resistance obtained by the acid oxidation method are high, the alkaline oxidation method is preferred in the industry because its color is not beautiful enough and it is not a pure oxide film.

The profitability of metal surface blackening treatment is affected by a variety of factors, including the complexity of the treatment process, the cost of the equipment required, the efficiency of the treatment, and the market demand. The specific profit situation needs to be analyzed in detail according to the actual situation.

Whether or not sandblasting is required depends on the specific process requirements and the condition of the metal surface. Sandblasting cleans metal surfaces, removes oil and rust, and provides a better basis for subsequent blackening treatments. If the metal surface is in good condition, sandblasting may not be necessary.

Books on blackening of metal surfaces can be referred to by specialized books or online resources, which often provide detailed process flows, technical points, and case studies to help understand and master the blackening process.