Synthesis and Magnetic Properties of MnBi(LTP) Magnets With High-Energy Product

초록

MnBi magnets were prepared by melt-spinning, annealing, ball-milling, magnetic alignment, and subsequent hot compaction process. Mn-Bi melt-spun ribbons contained mainly unreacted Mn and Bi phases, including the low-temperature phase of MnBi. To increase the amount of this MnBi phase, these melt-spun ribbons were annealed under an oxygen-controlled atmosphere. As a result, a maximum saturation magnetization value of 57.90 emu/g was obtained when the melt-spun ribbons were annealed at 300 degrees C for 12 h. Bulk magnets fabricated by magnetic alignment and hot compaction processes showed a density of 8.71 g/cm(3), a M-r/M-s ratio of 0.79, and a (BH)(max) value of 6.7 MGOe at room temperature. With the temperature increasing, the coercivity changed from 6387 Oe at room temperature to 18 540 Oe at 150 degrees C and a (BH)(max) measured 5.5 MGOe at 150 degrees C.

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