Research Alloy NdFeB Permanent Magnet Surface Plating Zn-Fe

NdFeB permanent magnet which have great performance of magnetic properties, have widely used in the field of electronics, aviation and aerospace, transport, domestic appliances in recent years. However, because of its specific composition and structure, NdFeB permanent magnet have the inherent deficiency,the low corrosion resistance. Electroplating Zn-Fe alloy on the surface of the NdFeB permanent magnet could make up the deficiency which could not destroy its magnetic properties. In this paper, a Zn-Fe alloy on the NdFeB permanent magnet was investigated and prepared by electrodepositing. And the processes of the electroplating and pro-electroplating treatment were studied, which effectively improve the corrosion resistance of the magnet. The main conclusions are as follows:The electroplating and the pro-electroplating process of Zn-Fe alloys on the NdFeB permanent magnet were optimized by using the method of orthogonal design. The corrosion resistance, hardness and the iron content of the coatings were also determined by using the salt spray test, potential dynamic polarization curve, EIS, microhardness tester, EDS and so on. At the same time, the range analysises of the experimental results were performed by using the range analytical method and the influence of various factors on the properties of Zn-Fe alloys were obtained. The analysises conclude that the factors affect on the Zn-Fe alloy by means of affecting the iron content and the structure of the coating. The result shows that the process parameters of current density, FeSO4concentration and pickling solution, have an important influence on the electrode position process. When the electroplating process comes to:work pieceâ†'polishing (polished to150#sandpaper)â†'oil removing pickling (3wt.%nitric acid solution)+ultrasonic cleaningâ†'washingâ†'activating. The current density Jk of1.5A/dm2, FeSO4concentration of10g/L, ZnCl2concentration of60g/L and the KC1concentration of210g/L were the best electrodeposited preparation process, and the comprehensive properties of Zn-Fe alloy coatings with the0.92%wt iron content were the best. The thickness, corrosion resistance (SST196hours without white rust) and micro-hardness of Zn-Fe alloy coating are great. The effection of the current density, electroplating temperature, electroplating time, PH value of the solution on the electroplating Zn-Fe alloy:in the area of low current density, as the increase with the current density, the iron content of the coating was slightly fluctuate in0.9%,when the current density increase above5A/dm2, the iron content increased immediately,and then stabled in a certain range; as the solution temperature increased, the iron content of the coating on the surface of the NdFeB permanent magnetic first increased and then decreased; the iron increased with the postponement of electroplating time; as the PH value increased, the iron content of the coating on the surface of the NdFeB permanent magnetic first increased and then decreased.