Enhanced Electric Resistivity of Die-Upset Magnets By Segmented NdF3 Addition

We report an approach to improve the electric resistivity of Nd-Fe-B die-upset magnets without sacrificing their magnetic properties very much. NdF₃ fine powders were segmentally added in the die filling with MQU-F powders and then were die-upset for magnets. Experimental results indicated that electric resistivity monotonically increases with the increase of NdF₃ addition, which is due to the formation of continuous segmented fluoride layers. When NdF₃ content reached 5.3 wt%, the electric resistivity almost increases by eight times. Magnetic properties exhibit no drastic decrease after the addition of NdF₃ and coercivity increases when adding 2.12 wt% of NdF₃.