Powder spraying is the use of corona discharge to cause powder coatings to adsorb onto the workpiece. The process of powder spraying is as follows: the powder gun is connected to the negative electrode, the workpiece is grounded (positive electrode), and the powder coating is sent into the spray gun by the powder supply system through compressed air gas. High voltage generated by a high-voltage electrostatic generator is added at the front end of the spray gun, and due to corona discharge, dense charges are generated nearby. When the powder is sprayed out from the nozzle, a circuit is formed to form charged coating particles, which are attracted to the workpiece with opposite polarity by the action of electrostatic force. As the amount of powder sprayed increases, the accumulation of charges also increases. When a certain thickness is reached, due to the electrostatic repulsion effect, the adsorption is not continued, so the entire workpiece obtains a certain thickness of powder coating. Then, the powder is melted, leveled, and solidified by heat, which is on the surface of the workpiece. Form a hard coating.