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

Nd-Fe-B permanent magnets doped with CuZn powders were prepared via conventional sintered method. The effects of CuZn 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 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 of 3.5 wt% and 4.5 wt% CuZn powders doping magnets is only 1 and 0 mg·cm after autoclaves test at 121 °C, 2 × 10 Pa for 500 h, respectively, which is much lower than that of the magnets without CuZn doping. Electrochemical results show that the CuZn powders doping magnets display more positive corrosion potential ( E ) and lower corrosion current density ( I ) than those of the original magnets without CuZn doping in sulphuric acid electrolyte and distilled water. It is, therefore, concluded that doping CuZn powders is a promising way to enhance the corrosion resistance of sintered Nd-Fe-B magnets. [ABSTRACT FROM AUTHOR]