Metals are affected by the environment, and the destruc […]
Metals are affected by the environment, and the destructive damage caused by chemical or electrochemical reactions is called corrosion. Almost all metal products have certain types of corrosion in certain environments, and the drill tails are Metal products naturally cannot avoid the problem of metal corrosion. When the environment and time are different, the corrosion phenomenon is also significantly different. There are many polluting industries, such as steel, petrochemical, thermal power generation, etc. In addition, in recent years, steam and locomotives have grown substantially, and a large amount of exhaust gas has been emitted, which is filled with corrosive sulfides and nitride gases and particles. The main cause of metal corrosion.
Surface anti-corrosion treatment refers to the application of a protective layer on the metal surface by various methods. The function of the surface is to isolate the metal from the corrosive environment to suppress the occurrence of the corrosion process, or to reduce the contact between the corrosive medium and the metal surface to prevent or Reduce the purpose of corrosion. The protective layer should meet the following requirements: 1. Corrosion resistance, wear resistance, high hardness, 2. Tight structure, completeness, small pores, 3. Strong bonding with the base metal, good adhesion, 4. Uniform distribution and certain thickness. The protective layer is generally divided into two types: a metal coating and a non-metal coating. The metal coating refers to forming a protective layer on a metal surface which is easily corroded by a metal or alloy having high corrosion resistance, and the coating is also called a plating layer. There are quite a number of methods and types of metal plating, the most common of which is electroplating, followed by molten metal immersion (hot dip) and chemical surface treatment.
Non-metallic coating refers to the use of organic polymer materials such as paints, and inorganic materials such as ceramics to form a protective layer on the surface of metal equipment or parts. The protective layer can completely isolate the base metal from the environmental medium and prevent the base metal from being corroded by contact. Corrosion caused by the medium.