The main problem of NdFeB plating protection


(1) The consistency and stability of production quality […]

(1) The consistency and stability of production quality are poor, and the product qualification rate is low. The plating quality of different batches of magnets on the same production line fluctuates greatly, and the pass rate of one-time plating is relatively low. Since electroplating is downstream of the NdFeB production process line, once the electroplating process is in trouble, the labor accumulation on the product cannot be converted into market value, and it also causes great waste of resources. In order to increase production, China's magnetic material enterprises have many product lines and specifications. Usually, magnets of different processes and magnets of different specifications coexist on the same plating line. Because the structure and structure of NdFeB magnets have much more influence on the electroplating process than steel parts, magnets of different grades and different shapes have a great influence on electroplating film formation, which is one of the important reasons for the fluctuation of coating quality. In addition, the degree of automation in the electroplating production process, the fluctuation of the quality of the pre-processing of the magnet workpiece before entering the electroplating process, the excessive influence factors of the pre-plating process and the electroplating process, and the imperfect implementation procedures are also leading to the fluctuation of the final product quality. The important reason for the low pass rate. Our process and management have room for further improvement compared to the Japanese level.
(2) Environmental issues
Regardless of environmental protection or technical barriers, the international inspection of environmental protection indicators for electroplating products is becoming more and more strict. The most pressing problems in the current industry are: the hexavalent chromium problem of galvanizing passivation, the problem of excessive lead and cadmium content in the coating, and the improvement of the requirements for the treatment of the three wastes.
Zinc-plated magnets typically require chromate passivation. The chromium in the passivation film layer is mainly in the form of trivalent and hexavalent forms. Among them, trivalent chromium acts as a network of skeletons, which can make the film have a certain thickness and strength. The hexavalent chromium is dispersed in the network and has self-repairing effect. Very corrosive. However, hexavalent chromium has been recognized as a cause of lung cancer. The final ban on the use of chromate has become an inevitable trend. The adoption of new environmentally friendly chromium-free passivation technology is imminent. The chromium-free passivation treatment mainly includes inorganic passivation (using transition elements, rare earths, silicates, etc. instead of chromate passivation) and organic passivation (using humic acid, tannic acid, epoxy resin, acrylic resin, Diaminotriazole and its derivatives are substituted for chromate passivation). Among them, some of the corrosion-free coatings obtained after chrome-free passivation have approached or even exceeded chromate passivation in some respects, which is promising, but limited due to high cost and inability to adapt to large-scale industrial production. Their promotion and use.