Enhancement of corrosion resistance in sintered Nd-Fe-B permanent magnet doping with different CuZn5 contents

摘要

Nd-Fe-B permanent magnets doped with CuZn_5 powders were prepared via conventional sintered method. The effects of CuZn_5 contents on magnetic properties and corrosion resistance of the magnets were systematically studied. It shows that the remanence,coercivity, and maximum energy product decrease gradually with the increase in CuZn_5 doping content. The magnet's corrosion kinetics in autoclaves environment and its electrochemical properties in electrolytes were also examined. It is interesting to see that the weight loss of3.5 wt% and 4.5 wt% CuZn5 powders doping magnets is only 1 and 0 mg·cm^(-2) after autoclaves test at 121℃,2 ×10~5 Pa for 500 h, respectively, which is much lower than that of the magnets without CuZn_5 doping. Electrochemical results show that the CuZn_5 powders doping magnets display more positive corrosion potential(E_(corr))and lower corrosion current density(I_(corr)) than those of the original magnets without CuZn_5 doping in sulphuric acid electrolyte and distilled water. It is, therefore, concluded that doping CuZn_5 powders is a promising way to enhance the corrosion resistance of sintered Nd-Fe-B magnets.