非晶質粉末の固化成形により作製したナノ結晶Fe-Rich Fe-Nb-Nd-B磁石 (<特集>ハード材料)

概要

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Nanocrystalline bulk Fe_<88>Nb_2Nd_5B_5 and Fe_<86>Nb_2Nd_7B_5 alloys were made by consolidating amorphous powders with a spark-plasma-sintering method and subsequent annealing. Bulk alloy made by consolidating amorphous powders has a higher density than that made by consoli-dating crystalline powders, presumdbly becaude the amorphous alloy softens around the crystallitie temperature.Bulk Fe_<88>Nb_2Nd_5B_5 and Fe_<86>Nb_2Nd_7B_5 alloys made by consolidating amorphous powders at a temperature of 873 K and a pressure of 636 MPa have a density of 7.5g/cm^3, and form a nanocrystalline composite structure of bcc-Fe, Fe_3B, and Nd_2Fe_<14>B phases with grain sizes of 20-40 nm after annealing at 1023 K. Nanodrystalline bulk alloys show hard magnetic properties, remanence (J_r) of 0.83-1.0T, coercive force (H_<cJ>) of 190-290 kA/m, and maximum energy product (BH)_<max> of 43-49 kJ/m^3.
社団法人日本磁気学会の論文
1997-04-15