Research Progress Of Electrical Explosion Spraying Method

Electrical explosion spraying is a new method of thermal spraying, which uses high voltage to pulse discharge on the spraying material, and the instantaneous high current heats and explodes it. High temperature particles are produced and sprayed to the surface of substrate with shock wave to form coating. It is characterized by high particle velocity and small equipment size, which is suitable for spraying on the inner wall of the cavity. In this paper, the development status of electrical explosion spraying method is reviewed, which has experienced free, directional and constrained electric explosion spraying. The free spraying electrode is directly contacted, which causes serious burning damage and limits the pipe diameter. It is only used for the inner wall of small diameter pipe/hole. Ceramic materials are commonly used in the confinement chamber of directional spraying, which are easy to break or ablate during explosive impact. These problems can be solved by using ablation material to make the confinement cavity and introducing current into the gas discharge in constrained spraying. Secondly, the characteristics of the coating prepared by this method are described, that is, the coating is metallurgically bonded with the substrate. The compact coating with ultra-fine grain and nano-crystalline structure is formed, which has good wear resistance, corrosion resistance and high hardness. Then the relationship between the process parameters and the coating is given. The energy density and spraying distance are the main factors affecting the coating performance. Finally, the problems to be studied in the future are analyzed, and the development trend of electric explosive spraying method is prospected.