Plasma spraying method of white corundum wear-resistant material
Arc spraying method of white corundum wear-resistant material flame spraying method of white corundum wear-resistant material
Plasma spraying uses a non-transfer compressed arc between a tungsten electrode and a water-cooled copper electrode (usually as an anode) to obtain a high-temperature and high-speed plasma jet for spraying. The plasma temperature of the compression arc can be as high as 1000℃ or more, and the exit velocity of the plasma jet can reach 800m/s. Plasma spraying is usually divided into atmospheric plasma spraying, low-pressure (also known as vacuum) plasma spraying, high-pressure plasma spraying and water stable plasma spraying according to the method of plasma arc generation and working atmosphere.
Atmospheric plasma spraying is spraying in an atmospheric atmosphere. The low-pressure plasma spraying is sprayed in a closed room with controllable pressure and atmosphere. By adjusting the atmosphere, the interaction between the spraying atmosphere and the molten particles can be controlled. For example, spraying the active metal material coating in an inert atmosphere can avoid high temperature molten metal. The oxidation of the puller reduces the content of oxides in the coating. The high-frequency plasma generated by the high-frequency power supply has a low flame flow speed, which can fully melt the sprayed material. Since the generation of high-frequency plasma does not require electrodes, the plasma atmosphere is controllable, and reactive gas can be added to the ion gas to make it react with the sprayed material to obtain a different structure from the original material composed of the sprayed material and the reaction product. Composite coating, this method is also known as reactive thermal spraying. Water-stabilized plasma spraying uses water vapor as the plasma gas, which has high enthalpy, so a plasma jet with a power of up to 200kw can be obtained, with high power and high productivity. Forming of ceramic materials.
Supersonic plasma spraying is based on high-energy plasma spraying (80kw level), and uses the “expanded arc” that occurs when a non-transfer plasma arc and high-speed airflow are combined to obtain a stable spring set of supersonic plasma jets for spraying. . In the mid-1990s, the American TAFA company launched the “PIAZJet” supersonic plasma spraying system with 270kw high power and large gas flow (21 m³/h). In China, a high-efficiency supersonic plasma spraying system with low power (80kw) and small gas flow address (6m³/h) has been successfully developed in China. The spray gun adopts the single anode structure of Laval nozzle profile. The length of the compression channel is shortened, and the internal powder feeding structure is applied, which effectively reduces the energy consumption.