Plasma spraying is a common spraying form, what is plasma spraying?

       Plasma spraying is a common spraying form, what is plasma spraying?

       Plasma spraying arc is a compressed arc, which can be divided into three different forms according to the different methods of electrification. One type is a non transfer arc with the positive electrode connected to the nozzle, and the workpiece is not charged at this time. The second type is a combined arc, where the nozzle and workpiece are both connected to the positive electrode. Compared to a free arc, a plasma arc has a finer arc column, a higher current density, and a higher degree of ionization of the gas, So plasma spraying with high temperature, concentrated energy, and good arc stability generally adopts a non transfer arc, which generates a direct current arc between the cathode and anode. This arc can heat and ionize the introduced working gas into a high-temperature plasma body, and spray it out from the nozzle to form a plasma flame. The powder is fed into the flame by the feeding gas, which is then melted, Then it is accelerated and sprayed onto the substrate material to form a film. The working gas can be nitrogen gas, or some hydrogen gas can be added to the nitrogen gas, or a mixture of argon and nitrogen gas can be used.

       The parameters of a plasma arc can be changed over a large range, but the co temperature does not change over a large range.

       Generally speaking, there are many parameters that affect the heating performance of a plasma arc, such as the intensity of the current, the composition and flow rate of the discharge gas, the size and shape of the nozzle, and the distance between the anode and cathode. The general plasma spraying electrode equipment mainly includes: spray gun, powder feeder, rectifier power supply, gas supply system, water cooling system, and control.

       The spray gun in plasma spraying is actually a non transfer type plasma arc generator, which is the most critical component in plasma spraying. The electricity, gas, powder, and water of the entire system are concentrated on it. The structure of the spray gun in plasma spraying is very diverse, but the basic construction principle is the same.