The development background of thermal spraying technology

       Corrosion and wear are the main forms of failure of materials and components. The economic losses caused by corrosion and wear in developed countries account for about 4% to 5% of the gross national economic output each year, and the losses are very serious. As an important technology in surface engineering, thermal spraying technology plays a role in surface strengthening and protection of workpieces. A variety of functions show strong advantages in solving the increasingly demanding multiple requirements of the surface of modern engineering structural components.



    The development of thermal spraying technology can be roughly divided into three stages.

    1) Simple thermal spraying process

    M.U.Schoop, a Swiss doctor of engineering, invented metal solution spraying in 1910, creating a new field of thermal spraying technology. Schoop successfully developed a wire flame spray gun and an arc spray gun in 1912 and 1916, respectively, and wire flame spray and arc spray became the main thermal spraying methods at that time. By the 1930s, the American Metco Metal Spraying Company had successively developed some new arc spray guns, and developed the Metco-p powder flame spray gun. Thermal spray technology began to be widely used in ships, steel structures, and water gates. and other long-term protection of steel products.

    2) Thermal spray technology

    Since the 1950s, the United States, Britain, Germany and other countries have vigorously developed thermal spraying technology, and a variety of new thermal spraying processes have emerged here. In the early 1950s, flame spray welding equipment appeared; in the late 1950s, the United Carbide Company of the United States successfully developed gas repeated explosive spraying; the emergence of plasma spraying technology in the 1960s enabled thermal spraying technology to be used in aerospace and aviation. From the 1970s to the 1990s; thermal spraying technology developed in the direction of high energy, high efficiency and high speed, and supersonic flame spraying technology and high-energy plasma spraying technology began to appear (the representative high plasma spraying equipment is Metco's 7M system ) and high-speed arc spraying technology. At the beginning of the 21st century, the Armored Forces Engineering College developed a supersonic plasma spraying system with independent intellectual property rights, and took the lead in promoting this technology to engineering applications.

    3) Thermal spraying industrial system

    From the first melt spraying device invented by Schoop to the current computer-controlled plasma spraying equipment, the spraying equipment is partially set, serialized and standardized. The materials that can be sprayed are metals and their alloys, organic plastics, and their composite powders have been formed into series and standard powders. The application field of coating ranges from simple long-term protection, repair of used parts to remanufacturing and technology, and pre-protection of new parts, which has become an essential and important process technology in the field of manufacturing technology. The application of coating quality online detection, spraying heat source temperature field distribution, particle velocity measurement, and online diagnosis technology has greatly improved the stability and reliability of coating preparation.