Thermal spraying process of nickel-chromium-chromium carbide wear-resistant coating

       At present, many domestic and foreign military aero-engine manufacturers have adopted plasma spraying protection technology for parts processing to improve the wear resistance and high temperature resistance of engine parts, reduce the working temperature of parts, and improve the service life of aero-engine parts. . Among them, thermal spraying uses a certain heat source to heat the coating material to melt or soften, and atomize it into fine droplets or high-temperature particles under the action of high-speed airflow, which are sprayed onto the surface of the pretreated substrate at a certain speed. , a surface strengthening technology to form a special functional protective coating. According to different heat sources, thermal spraying can be divided into flame spraying, arc spraying, atmospheric pressure plasma spraying, low pressure plasma spraying, supersonic flame spraying, explosive spraying, etc.



Plasma spraying is widely used in the field of small and medium-sized aero-engine manufacturing. It uses plasma arc as a heat source to melt powder and spray the expanded plasma gas at high speed to the surface of pre-treated substrate to form a coating. Due to the high temperature of the plasma arc (the center temperature of the arc column can reach 15000-33000K) and the concentrated heat, it can melt all high melting point powder materials, which cannot be achieved by ordinary flame spraying and arc spraying; , hydrogen is used as an auxiliary gas, which greatly reduces the oxidation degree of the sprayed powder, thus giving the coating the advantages of low impurity content and high purity; in addition, the spraying energy is large and the powder particle flying speed is fast, giving the coating high density (88 %~90%), low porosity (3%~8%), and high bonding strength (40~50MPa).