Cold spray is a solid-state process cut a striking figure. The method can be accelerated to kinetic energy of solid particles of ultrasound in impact to the plated surface is changed into heat energy, so as to complete the welding metallurgy. The principle of this technology is: for each metal has its specific, with temperature dependent critical particle velocity, when the particle motion over the speed will be welded to the plating on.
In Ji'nan, the traditional process of fluorocarbon spraying, due to higher temperature, coating and plating materials will be oxidation, generating metallurgy deformation and residual Zhang Yingli. On the other hand, cold spray coating workmanship, porosity is very low (<0.5%), and the anti oxidation, anti phase transition, a variety of metal, metal ceramic or other material combinations can reduce the Zhang Yingli.
In Ji'nan, fluorocarbon spraying technology, high pressure helium or nitrogen (350 to 450 pounds per square inch) used as carrier gas can be accelerated to supersonic speed of spraying material. The gas is heated and forced through a focused divergent nozzle (deLaval), it is accelerated to the speed of ultrasound (greater than 1000 m / s). Spray particles in the upper direction is along the axial injection nozzle.
In Ji'nan, fluorocarbon spraying technique, nitrogen or air is pressurized to 70 to 15 pounds per square inch, and the downstream side in the divergent part of powder spraying nozzle along the radial injection. Low pressure cold spraying system is portable, the operation is more economical, particle speeds up to 800 m / s.. Portable cold spraying machine can be used for aluminum, copper, zinc and other metal combined spraying. Easy to carry features make low pressure cold spraying machine is more suitable for field maintenance and repair.
Cold spray technology is an effective method in the generation of aluminum coating thickness on the surface of magnesium alloy, the method of surface preparation requirements is not high, but without taking into account the plating mechanical or thermal properties. Aluminum coating exhibit the ability to prevent and electric corrosion of magnesium element. Most of the time, the need for battery corrosion protection only around the steel fasteners, and cold spray is just a exposure to local protection of magnesium surface technology innovation.
However, in order to understand and improve the cold spray process is necessary to study more fully, especially for the continuous development of innovative combination of a variety of materials and the cold spray process itself, and better use of materials in the future technology, much work remains to be done.