Anticorrosion and Application of Plasma Spraying on Steel Parts

       

Thermal spray aluminum technology is a new technology for surface protection, surface strengthening and surface repair of steel parts.







Due to the long-term exposure of steel parts to various atmospheres, immersion of different water quality and erosion of different media, they are corroded to different degrees. About one tenth of the steel produced every year becomes rust, and about 30% of steel equipment is damaged by corrosion. In developed countries, the annual loss due to metal corrosion accounts for 1 to 4% of the gross national product. The economic loss caused by corrosion in my country's coal system is as high as 800 million yuan every year. With paint protection, the protection period is generally two or three years, and the shortest is only one year. Frequent maintenance will cause a lot of consumption of manpower, material and financial resources. By spraying aluminum on the steel surface and sealing the holes, a long-lasting anti-corrosion composite coating can be prepared. The effective protection period is generally up to 20 to 30 years. Therefore, it is our urgent task to vigorously publicize and promote the application of thermal spray aluminum technology in the anti-corrosion of steel parts.

Characteristics of aluminum coating: The dense oxide film on the surface of metal aluminum makes it have good corrosion resistance and oxidation resistance, so aluminum can resist the corrosion of chemical media, especially the sulfur dioxide atmosphere and have a certain protective effect against oxidizing acids. , The standard electrode potential of aluminum is -1.66 volts, which is much lower than the standard electrode potential of iron, so it is sprayed on steel parts. In the presence of electrolyte, the coating is an anode protective layer to protect the substrate from corrosion.

Due to the special advantages and economic benefits of thermal sprayed aluminum, in recent years, various countries have used it for steel components of railways, highways, and urban overpasses, high-voltage transmission towers, oil extraction derricks, TV relay towers, large transport belt racks, and various large containers. , chemical reaction towers, ships and ships, sheet steel components, many steel components exposed to the atmosphere, high temperature, industrial atmosphere, chemical atmosphere and immersed in various solutions, steel components for various large-scale pipeline engineering , Bar steel, etc.