The main connotation of thermal spraying technology

       The main connotation of thermal spraying technology should include three aspects: material, equipment and process (including pretreatment, spraying process and post-processing). The initial thermal spraying can only use metal wires with a lower melting point as the material, and use the flame as the heat source to spray anti-corrosion coatings and perform maintenance services, so it is called "metal spraying". The advent of self-fluxing alloy powders during World War II enabled powder flame spraying to gain large-scale industrial applications. After the war, the aviation and aerospace industries developed rapidly, and high melting point metals or alloys and ceramic materials became practical with the advent of atmospheric plasma spraying technology. The successful development of self-adhesive composite powders represented by nickel and aluminum has played an important role in further improving the bonding force of the coating.

With the improvement of spraying equipment and the subsequent development of new processes such as explosive spraying, low-pressure plasma spraying, and supersonic flame spraying, it is possible to achieve high-quality coatings, and thermal spraying materials for various purposes have emerged accordingly. For a long time, thermal spraying equipment and processes have been pursuing high energy of heat source and high speed of particles, and pursuing high efficiency of spraying process through operation automation, and finally improving the quality and stability of coating. Over the past century, thermal spray materials have developed from several metal wires at the beginning to hundreds of thermal spray materials to meet the needs of different process operations and different use characteristics. The thermal spraying material obtains a coating with a certain composition and structure through the spraying method (equipment, process), and then obtains the desired coating characteristics. In a broad sense, thermal spray technology is a means of material compounding. It can be said that the functional diversity of thermal spray coatings or their adaptability to different specific uses depends on the material. The development of thermal spray materials and spray methods promote each other, and together they promote the progress of the entire thermal spray technology.