What are the types of plasma arcs in plasma spraying technology?

China's economic strength is constantly growing, and the protection of materials and workpieces has also received attention from many people. At present, the demand for plasma spraying equipment in China is constantly increasing, which is inseparable from plasma arc. At present, plasma arcs can be divided into three categories:

1. Non transfer arc.

The connection between the positive electrode and the nozzle is not charged, while a non transfer arc is generated between the nozzle and the cathode. The working gas is heated by the arc between the cathode and the nozzle, causing complete or partial ionization, and then ejected from the nozzle. Particle spraying uses this type of plasma arc.

2. Transfer arc.

When the arc leaves the spray gun, it will transfer to the plasma arc of the workpiece. In this case, the nozzle is not connected to the power supply, the workpiece is connected to the positive electrode, and the arc flies between the cathode and anode of the spray gun. The working gas is transported around the arc and then sprayed out from the nozzle. This plasma arc is used for plasma cutting, plasma arc welding, and plasma arc melting.

3. Composite arc.

The non transfer arc ignites the transfer arc and heats the metal powder, while the transfer arc heats the workpiece to produce a molten pool on the surface. In this case, both the nozzle and the workpiece are connected to the positive electrode. This plasma arc is currently used for plasma spray welding. During plasma spraying, a direct current arc is generated between the cathode and the nozzle. The arc heats and ionizes the introduced working gas into high-temperature plasma, and the nozzle sprays a plasma flame. The nozzle outlet temperature can reach 15000-20000 ° K, but it decays quickly. Send the powder into the flame to melt and accelerate it through the flame flow to obtain 150. Spray at the above speed of m/s onto the substrate to form a thin film.

Plasma spraying technology has always been a key focus of development in China, so technicians must understand this knowledge. If you want to learn more, you can follow us more.