Electrogalvanizing method of neodymium iron boron magnet

Abstract

The invention discloses an electrogalvanizing method of a neodymium iron boron magnet. A first electroplating solution adopted in primary electrogalvanizing treatment is a zinc sulfate solution, the zinc sulfate solution is prepared by mixing 200-400 g/L of zinc sulfate, 20-50 g/L of boric acid and water, the pH value of the zinc sulfate solution is 3.5-5.5, and the temperature of the zinc sulfate solution is 20-40 DEG C; and a second electroplating solution adopted in secondary electrogalvanizing treatment is an alkaline zincate solution, the alkaline zincate solution is prepared by mixing 6-20 g/L of zinc oxide, 80-140 g/L of sodium hydroxide and water, the pH value of the alkaline zincate solution is greater than 12, and the temperature of the alkaline zincate solution is 20-40 DEG C. The method has the following advantages: the zinc sulfate solution does not corrode the neodymium iron boron magnet, the combination consistence of a first galvanizing layer and the neodymium iron boron magnet is good, a second galvanizing layer does not corrode the neodymium iron boron magnet, the combination force consistence of the second galvanizing layer and the neodymium iron boron magnet is good, and the obtained neodymium iron boron magnet has good anticorrosive performance.

Description

technical field [0001] The invention relates to an electrogalvanizing method, in particular to an electrogalvanizing method for an NdFeB magnet. Background technique [0002] Compared with nickel plating, zinc coating has the advantages of low cost, simple operation and good bonding force with NdFeB magnets, and has been widely used in the surface treatment industry of NdFeB magnets. [0003] There are mainly two kinds of existing electrogalvanizing methods, which are respectively an electrogalvanizing method using a zinc chloride solution as an electroplating solution and an electrogalvanizing method using a zinc sulfate solution as an electroplating solution. Zinc chloride solution is used as the electroplating zinc method of the electroplating solution. The zinc chloride particles are relatively small, the electroplating efficiency is high, the deposition rate is fast, and the electrolyte is easy to maintain. However, because the chloride ions contained in its main salt (...

AI Technical Summary

Problems solved by technology

Zinc chloride solution is used as the electroplating zinc method of the electroplating solution. The zinc chloride particles are relatively small, the electroplating efficiency is high, the deposition rate is fast, and the electrolyte is easy to maintain. However, because the chloride ions contained in its main salt (zinc chloride) will It reacts with the neodymium element in the NdFeB magnet, causing the corrosion of the NdFeB magnet. On the one hand, the magnetic performance of the NdFeB magnet is reduced. The shear force test value fluctuates within the range of 15MPa-30MPa

Compared with the electrogalvanizing method using zinc chloride solution as the electroplating solution, the electrogalvanizing method using zinc sulfate solution as the electroplating solution does not cause corrosion of the NdFeB magnet substrate, and the bonding force between the galvanized layer and the NdFeB magnet is consistent. The property is also good (the shear force test value fluctuates in the range of 20MPa-30MPa), but its main salt (zinc sulfate) has larger particles, the galvanized layer is rougher, the dispersion ability is poor, and the galvanized layer has many pores. This leads to poor corrosion resistance, and the salt spray test generally can only reach 24 hours