Nd-Fe-B permanent magnets with a small amount of Cu nano-particles doping have been prepared by conventional sintered method.Effects of Cu content on magnetic properties,corrosion resistance,and oxidation properties of the magnets have been studied.It shows that the coercivity rises gradually,while the remanence decreases simultaneously with increasing Cu doping amount.Microstructure observation reveals that Cu element enriches mainly the Nd-rich phase.Autoclave test results show that the corrosion rate of the magnets decreases with increasing Cu content.After oxidation,the maximum energy product loss of the magnets with 0 and 0.2 wt% Cu nano-particles doping are 6.13% and 0.99%,respectively.Therefore,it is concluded that Cu nano-particles doping is a promising way to enhance the coercivity and corrosion resistance of sintered Nd-Fe-B magnets.
Nd-Fe-B permanent magnets with a small amount of Al nano-particles doping were prepared by conventional sintered method. Effect of Al content on magnetic property, corrosion resistance and oxidation properties of the magnets were studied. Investigation showed that the coercivity rose gradually, while the remanence decreased simultaneously with increase of Al doping amount. Further investigation revealed that most Al element diffused into the main phase and some Al element diffused into the Nd-rich phase. The autoclave test results showed that the corrosion rate of the magnets decreased with Al content increasing. After oxidation, the maximum energy product losses of the magnets with 0.0 wt.% and 0.2 wt.% Al nano-particles doping were 6.13% and 3.99%, respectively. Therefore, Al nano-particles doping was a promising way to enhance the coercivity and corrosion resistance of sintered Nd-Fe-B magnet.
