Explain what is the working principle of supersonic spraying? Explain what is the working principle of supersonic spraying? 解释一下超音速喷涂的工作原理是什么？ Explain the working principle of supersonic spraying by what? 用什么来解释超音速喷涂的工作原理？

       Supersonic spraying is a high-temperature, high-speed combustion flame flow generated by the combustion of propane, propylene, or other hydrocarbon gases or hydrogen and high-pressure oxygen in a combustion chamber or special nozzles. The combustion flame velocity can reach Mach 5 (1500m/s). )above. Usually called HVOF (High Velocity Oxygen Fuel). The powder is fed into the flame axially, and the ejected particles can be heated to a molten or semi-molten state, and accelerated to a speed as high as 300-500m/s, or even higher, so as to obtain high bonding strength and compactness. High-quality coating. .Supersonic flame speed is very high, but the temperature is relatively low. For WC-Co cemented carbide, it can effectively inhibit the decomposition of WC during the spraying process. The coating not only has high bonding strength, but also is dense and has excellent wear resistance. Its wear resistance greatly exceeds that of plasma sprayed coatings, which is equivalent to explosive sprayed coatings, and also exceeds electroplated hard chrome coatings and sprayed molten coatings. It is extremely widely used.



The working principle of supersonic spraying: the liquid that enters the combustion chamber from the small hole burns, such as kerosene. After being atomized and mixed with oxygen, it is ignited and a strong gas phase reaction occurs. The heat released by combustion causes the product to expand violently. The expanding gas flows through the Laval nozzle. Constraints on the formation of high-temperature flame flow in supersonic spraying. Flame heating accelerates the sprayed material to reach the surface of the substrate, forming a high-quality coating



When the particles impact the individual surface layer, the high speed can form a larger impact, and the particles have strong deformability, which is beneficial to improve the adhesion and density of the coating. The surface layer characteristics of supersonic spraying are due to the high particle velocity, which has achieved a wide range of applications in the industry.