Effects of Sn Addition on the Microstructure and Magnetic Properties of MnBi Bulk Magnets

The Sn addition MnBi bulk magnets with high density and superior coercivity (H-c) were prepared by hot compaction. It was found that the added Sn was dispersed between the MnBi particles as an intergranular phase. The appropriate intergranular phase content could be beneficial in improving the H-c due to the strong magnetic isolation effects. The H-c of the MnBi/Sn bulk magnet was increased from 8.6 kOe to 11.5 kOe as the Sn addition contents were increased in the range of 0 wt.% to 5 wt.%. A relatively high squareness (M-r/M-s) of 0.91 was obtained for the 1 wt.% Sn addition Mn56Bi44 bulk magnet exhibiting the maximum energy product (BH)(max) of 7.8 MGOe with high H-c of 10 kOe at room temperature. (C) 2021 Elsevier B.V. All rights reserved.