Powder coating makes use of the corona discharge phenomenon to make powder coatings adsorb on the workpiece. When spraying, the spraying gun connects the negative pole, the workpiece is grounded (positive pole). The coating powder is fed into the spraying gun by compressed air. The high voltage generated by a high voltage electrostatic generator is added to the front of the spraying gun. So that the powder is electrostatically charged when sprayed,

which are attracted by the electrostatic force to workpieces with opposite polarity. When they reach a certain thickness, because of the electrostatic repulsion effect, they will not continue to adsorb, so that the whole workpiece can get a certain thickness of powder coating. Then workpieces pass through a heated room where the powder is melted, leveled and solidified under 200 degrees Celsius. A hard film is formed on the surface of the workpiece. The powder coating forms a much harder and thicker layer than traditional liquid paint. It is widely used for home use devices, outdoor decoration materials, etc. With a proper kind powder, aluminium extrusion with powder coating can last over decades without much color change outdoors.