1. Characteristics and development of surface engineering and thermal spraying technology

Surface engineering is a system engineering that changes the morphology, chemical composition, microstructure and stress state of solid metal and non-metallic surfaces through surface coating, surface modification or composite treatment of various surface engineering technologies after surface pretreatment, so as to obtain the required surface properties.

Surface engineering is a synthesis of basic theories, technologies, and the latest achievements in many fields. Surface engineering technology manufactures a layer of coating or film on the surface of the matrix material, or endows the material with many special properties through surface modification, so that the surface properties of the material are much better than the material matrix, which can not only greatly extend the application field of the matrix material, but also solve the problem that the material cannot meet the environmental requirements in many fields. Surface engineering technology plays an irreplaceable and important role in solving common problems such as resources, energy, and environment encountered in human development.

Because the surface engineering technology is energy-saving and material-saving, it protects the precious resources that human beings rely on for survival, and also plays a very key role in environmental protection. In the 21st century, surface engineering technology will penetrate all walks of life, promote social civilization and improve the quality of life.

Thermal spraying technology is an important branch of surface engineering, which is to heat a certain linear and powdery material to a molten or semi-melted state through heat sources such as flame, arc or plasma, and spray the accelerated molten droplets to the substrate at high speed to form a coating. Coatings are resistant to abrasion, corrosion, high temperatures, and thermal insulation, and can repair part size reductions caused by wear, corrosion, or machining out-of-tolerance. The application of thermal spraying technology mainly includes: long-term anti-corrosion, mechanical repair and advanced manufacturing technology, mold making and repair, and manufacturing special functional coatings. At present, thermal spraying technology has been widely used in almost all industrial fields as well as household products (such as non-stick pans, infrared health care electric heaters, etc.).

At the end of the 20th century, thermal spraying technology developed very rapidly and was quickly popularized. Changes in the thermal spray market from 1980 to 2000 are shown in Table 1. By the end of the 20th century, plasma spraying was still dominant. It is worth noting that high-speed flame spraying (HVOF) is developing rapidly and will occupy 25% of the market share, ranking second. Arc spraying technology, due to its good economy and superior coating performance than flame spraying coating, will partially replace flame spraying technology to the third place.

(The article comes from the Internet)