Metal thermal spraying leaps into a new stage and develops in the direction of strengthening

       Corrosion and wear are the main reasons for the failure of materials and parts. According to relevant data reports, the economic losses caused by wear and corrosion in developed countries account for about 4 to 5% of the gross national economic output value each year. /10 will turn into rust. The annual loss caused by corrosion and wear in my country has reached hundreds of billions of yuan. Therefore, the promotion and application of metal thermal spraying technology is becoming more and more important in the construction of the national economy. At present, my country's metal thermal spraying technology has developed to a new stage. Its spraying technology has developed from oxyacetylene flame metal powder spraying (welding) to high-energy, high-speed advanced equipment, and its application range has changed from old repairs to waste. Develop in the direction of new product pre-protection and reinforcement.



Corrosion is one of the main reasons for the failure of mechanical components by the chemical or electrochemical action of the surrounding medium. It not only causes the loss of a large number of metal materials, but also the loss of production stoppage is more difficult to estimate, so people pay special attention to the chemical anticorrosion work. The thermal spray coating used in corrosive media, especially strong media corrosion, has not been able to break through before, the main reason is that the sealing agent has not been solved. As we all know, the spray coating has pores. If the sealing treatment is not carried out, various acids, alkalis and organic media will penetrate into the pores, causing the coating to fall off and affecting the anti-corrosion effect. According to the requirements of anti-corrosion engineering, my country has recently successfully developed dozens of types of sealing agents, such as polyester type, organic polymer type, resin type, plastic type, adhesive type, etc., which are suitable for acid, alkali, salt and organic matter. Corrosive environment, the operating temperature is 80℃～350℃. Using ceramic coating, oxide coating or metal or alloy coating, according to different media, choose appropriate sealing agent, which has been applied in many chemical corrosive media with good effect.



With the development and improvement of metal thermal spraying technology in my country, the requirements for the quality of the sprayed layer are getting higher and higher. In recent years, there have been many manufacturers of oxyacetylene flame plastic powder spraying equipment in China. Using this technology, it has been used in chemical storage tanks, pipelines, mud machine plates and frames in the ceramic industry, cloth guide rollers in the printing and dyeing industry, and belt type in the coal industry. Cast iron rollers for transporters, polymer injection equipment in the petroleum industry, and surface decoration have all been well used, making up for the lack of EFI. It opens up a new way for the application of plastic coating.



In recent years, many literatures have reported some high-temperature materials such as ceramics and intermetallic compounds. One of the most important should be MoSi2. This material has a sufficiently high melting point (Tm2030 ℃), moderate specific gravity and excellent high temperature oxidation resistance, the working temperature can reach 1700 ℃, it is an excellent high temperature oxidation resistant coating. At the same time, it is resistant to corrosion by inorganic acids and molten metals. As a coating material for high-temperature components of aviation and gas turbines, it is the latest research hotspot.



Engineering technical requirements such as wear resistance, heat resistance, oxidation resistance and corrosion resistance are the main functions of thermal spray coatings. Wear-resistant coatings, in particular, are the strengths of thermal spray technology. In recent years, thermal spraying technology has tried to play its specialty in high-tech fields such as bioengineering, superconductivity and composite materials, and even emerged and entered the practical stage.



Replacing metal with engineering plastics in the aviation and automotive industries, and improving efficiency due to weight reduction, is a new achievement of today's material revolution, and there are similar requirements in the electronics industry and machinery industry. Using thermal spray technology to achieve these requirements is indeed a shortcut, but many spray materials cannot be directly sprayed on plastic substrates. To this end, SULZERMETCO has specially researched a primer powder for spraying the surface of plastic substrates, which is favored by the market with high bonding strength, good surface morphology and low residual stress.



At present, metal thermal spraying technology is developing, and there are still many problems to be solved. However, most of the solutions to these problems revolve around the primary requirement of improving the quality of the coating, that is, mainly to improve the bonding strength and density of the coating, and to develop a variety of new thermal spraying equipment and materials. From the perspective of future development trends, the research on thermal spray system engineering will receive more and more attention. At present, many countries have strengthened the research on metal thermal spraying system engineering, that is, starting from failure analysis, through the optimization of surface pretreatment, spraying equipment, spraying materials and spraying process, the implementation process plan of metal thermal spraying is formulated. In the process of development, technology and other disciplines have crossed and infiltrated to form new surface treatment processes. For example, the combination of thermal spraying and heat treatment technology has emerged furnace sintering remelting and high-frequency induction remelting coating and infiltration technology; and electroplating technology. Combined with the coating process and coating process; combined with the casting process, there are sintering spray melting and electric spark sintering processes. Using new energy sources, laser remelting and electron beam remelting have appeared. It can be seen that the new fields of application of metal thermal spraying technology need to be further explored and developed.