Application and Development of Thermal Spray Technology in Metallurgical Industry

       

Thermal spraying technology is to heat certain materials to a molten or semi-molten state through a certain heat source, and then spray them on the surface of the coated substrate to form a coating with better performance than the original substrate, so that the original workpiece has a more excellent surface. performance, or to make the workpiece obtain one or more surface properties that the original matrix material does not have a film-like structure. These surface properties include wear resistance, corrosion resistance, heat resistance, oxidation resistance, heat insulation, insulation, electrical conductivity, sealing, disinfection , anti-microwave radiation and various other special physical and chemical properties. At present, thermal spraying technology has been widely used in many fields including aviation, aerospace, atomic energy equipment, electronics and other cutting-edge technologies, and has achieved good economic benefits.

Spraying materials include metals, ceramics and plastics. The formation of the sprayed layer includes the heating and melting stage of the sprayed material, the atomization stage of the droplets, the flying stage of the particles and the spraying stage of the particles. The combination of coating and substrate includes mechanical bonding, diffusion bonding, physical bonding and metallurgical bonding. When using exothermic spraying materials or spraying with high-temperature heat sources, the molten sprayed material particles will weld with the molten matrix, forming a metallurgical bond of micro-regions and improving the bonding strength of the coating and the matrix. The bonding between the particles in the spray coating is mainly mechanical bonding, and diffusion bonding, physical bonding, metallurgical bonding, etc. also work together.