Supersonic low-pressure cold spraying

　　1. Technical principle

　　Supersonic low-pressure cold spraying, also known as low-pressure cold spraying, is a new metal spraying process, which is different from traditional thermal spraying (superspeed flame spraying, plasma spraying, explosion spraying, etc.), does not need to melt the sprayed metal particles, and the temperature generated on the surface of the spraying substrate generally does not exceed 150 °C.

　　The principle of supersonic cold spraying technology is to use compressed gas to generate supersonic air flow through the scaled lava tube, send the powder into the supersonic air flow in the axial direction, form a gas-solid dual-phase flow, and after acceleration, hit the matrix under a complete solid, and a large plastic deformation occurs and is deposited on the surface of the substrate to form a coating.

　　2. Technical characteristics

　　(1) The temperature of the surface of the cold spraying substrate is lower than 150 °C, which will not cause internal stress in the substrate, and there is no deformation and phase change.

　　(2) The coating has no thermal stress and can be sprayed with a thick coating with a thickness of 10 mm.

　　(3) High coating bonding strength, 30~100MPa; Large cohesion, 30~100MPa.

　　(4) The coating is dense and has low porosity (<5%); High thermal conductivity (more than 90%).

　　(5) Good coating uniformity, high surface finish, Rz20~40.

　　(6) The particle flow section sprayed by cold spraying is small and narrow, and the orientation is good, and the local surface can be sprayed.

　　(7) One equipment can spray a variety of powders (aluminum, copper, zinc, nickel, lead, tin and babbitt alloy, etc.), and can prepare a variety of functional coatings (anti-wear, corrosion resistance, friction reduction, heat resistance, sealing, electrical conductivity, anti-sticking, etc.).

　　(8) It can be sprayed on any metal product, as well as on ceramic, glass and cement surfaces.

　　(9) Cold spraying has no high temperature, no dangerous gases and radiation, and is harmless to the environment.

　　(10) The equipment has a compact structure, easy to carry, and can be used in fixed occasions or in field conditions.