1.. Research Institute of function Materials，Central Iron and Steel Research Institute，Beijing 100081，China；
2.. Shanghai Aerospace Control Technology Institute，Shanghai 201109，China
Abstract：In this paper, sintered (MM, PrNd)-Fe-B magnets containing mischmetal（MM）were prepared by conventional
powder metallurgy process, and the effects of rare earth rich alloy on the microstructure and magnetic
properties of the magnets were studied. The aggregation of La and Ce in the grain boundary of MM7
(PrNd)24Fe74.99B1.01 magnet without rare earth rich alloy, can be eliminated by adding 6% of (PrNd)41Fe57.99B1.01 rare
earth rich alloy, and the coercivity of magnet can be increased from 11.15 kOe to 11.98 kOe. Microstructure analysis
shows that, after adding rare earth rich alloy, there is a double main phase structure in the magnet. Pr and Nd in
(PrNd)2Fe14B are replaced by La and Ce, with La and Ce in (MM, PrNd)2Fe14B being replaced by Pr and Nd. The
coercivity of the magnet is improved by the uniform distribution of La and Ce in the grain boundary and the dual
main phase structure.
2022, Vol. 32 
