Variation of magnetic properties with mischmetal content in the resource saving magnets of MM-Fe-B ribbons

摘要

Magnetic materials of MM-Fe-B (MM=mischmetal) ribbons were prepared using melt spinning method by varying the content of MM. The ribbons contain minor phases besides the main phase of Re_2Fe_(14)B. X-ray techniques show that the diffraction peak intensities of the minor phase Fe_3B vary with the content of constituent elements, indicating that the amount of minor phase could be tunable. The squareness of hysteresis loop is the best in MM_(13)Fe_(80.5)B_(6.5) ribbons, which should mainly ascribe to the less amount of minor phase. Henkel plots verify the more uniform magnetization reversals in MM_(13)Fe_(80.5)B_(6.5) ribbons, and the energy product achieves to the maximum of 12.74 MGOe with the coercivity of 6.50 kOe. With the increase of MM content the coercivity increases monotonically, and reaches to 9.13 kOe in MM_(15)Fe_(77.5)B_(7.5) ribbons, which should be related with the nature of the defects in the main phase. These investigations show that optimizing the content of constituent elements and phase constitution could improve magnetic properties in the resource-saving magnets of MM-Fe-B ribbons.