cold spray

       

Cold spray technology (CS: Cold Spray), also known as aerodynamic spray technology, refers to a method in which high-speed solid particles with a certain plasticity collide with the substrate and undergo strong plastic deformation to deposit and form a coating. Under normal conditions, the general concept is that when the solid particles collide with a certain matrix, the erosion effect of the solid particles on the matrix will be produced.
It should be said that cold spraying technology is different from traditional thermal spraying (traditional thermal spraying such as ultra-velocity flame spraying, plasma spraying, explosive spraying, etc.), it does not need to melt the sprayed metal particles, cold spraying uses compressed air to accelerate metal particles to zero speed, After being ejected from the nozzle, the metal particles directly hit the surface of the substrate and undergo physical deformation. The metal particles are flattened on the surface of the substrate and firmly attached. The metal particles are not melted in the whole process, and the temperature generated by spraying the surface of the substrate will not exceed 150℃-200℃.
There are two biggest characteristics of cold spraying: high speed and low temperature, which make it spray zinc, aluminum, copper, iron, nickel, titanium and other metals and stainless steel, bronze and other alloys, or are sensitive to temperature (nano, amorphous, etc.) , Oxidation-sensitive (Cu, Ti, etc.) and phase-transition-sensitive (cermet) materials, the advantages are obvious. In addition, the thermal impact on the substrate is small and the coating is dense, making it possible to spray coatings with a thickness of more than 10 mm. These special properties create special applications for cold spray: electrical conductivity, corrosion resistance, targets and 3D printing.