The characteristic of plastic electroplating is that it does not conduct electricity. It needs to be electrically conductive first, namely activation and electroless plating, so that a layer of metal film is firmly attached to the surface, and the subsequent electroplating is no different from metal electroplating. The problems in the process of using after electroplating are different. For metal electroplating, there is a potential difference between the substrate and the coating. When the coating potential is positive, it belongs to the cathode coating and can only play a mechanical protection role. Once the coating has pores or Damaged, in the presence of electrolyte, the substrate is corroded first, such as copper plating on steel; if the plating potential is relatively negative, it is an anodic coating, which not only has mechanical protection, but also electrochemical protection. When corroded, the coating will corrode first, such as steel For galvanizing, after removing the zinc layer of the waste galvanized products, we can see that the surface of the workpiece is still very good, and it is rarely corroded. This is the reason. For products that have been plated with copper, the bottom layer is often corroded into pits and bumps. Plastic electroplating does not have a metal bottom layer, but during multi-layer electroplating, there is also a potential difference between the coating and the coating. At this time, the coating with a negative coating potential is corroded first. We often see corrosion products on the surface of plastic electroplating parts. This is the reason.