Study of the correlation between the coercivity and averaged internal structure of Nd-Fe-B sintered magnets

Takeda, Masayasu  ; Suzuki, Junichi; Yamaguchi, Daisuke; Akiya, Takahiro*; Kato, Hiroaki*; Une, Yasuhiro*; Sagawa, Masato*

A neodymium iron boron (Nd-Fe-B) sintered magnet is the most powerful permanent magnet among the commercially available ones. Dysprosium (Dy), however, has to be added in Nd-Fe-B sintered magnets to keep the high above the room temperature or high-temperature applications. Dy-less or Dy-free Nd-Fe-B sintered magnets are now highly demanded because Dy is one of the rare metals. We performed small-angle neutron scattering (SANS) measurements of sintered Nd-Fe-B sintered magnets to elucidate the correlation between the coercivity and averaged internal structures of this magnet. Such correlation is a clue to achieve the Dy-less or Dy-free Nd-Fe-B sintered magnets. In this talk, we report the detailed results of the experiments and the correlation revealed by the SANS measurements.