TY - JOUR
T1 - Hard magnetic properties of bulk amorphous alloys
AU - Inoue, Akihisa
AU - Zhang, Tao
AU - Takeuchi, Akira
PY - 1997/3
Y1 - 1997/3
N2 - The amorphous phase in the Nd-Fe-Al and Pr-Fe-Al systems is formed in extremely wide composition ranges of 0 to 90 at% Fe and 0 to 93 at% Al by melt spinning. Ferromagnetic Ln90-xFexAl10 (Ln=Nd or Pr) bulk amorphous alloys with high coercive force at room temperature are obtained by a copper mold casting method. The maximum diameter of the cylindrical amorphous samples is 12 mm for the Nd-30%Fe-Al alloy and 3 mm for the Pr-30%Fe-Al alloys and decreases with deviating Fe content. Neither glass transition nor supercooled liquid region is observed in the temperature range before crystallization (T < Tx), which is different from other bulk amorphous alloys exhibiting wide supercooled liquid regions. The extremely high Tx/Tm and small ΔTm(=Tm-Tx) values are the reason for the achievement of large glass-forming ability in these systems. The bulk amorphous Ln60Fe30Al10 alloys are ferromagnetic with the Curie temperature (Tc) of 515 to 600 K which are much higher than those for Nd-Fe and Pr-Fe binary amorphous ribbons. The remanence (Br) and intrinsic coercive force (iHc) are 0.089 to 0.122 T and 277 to 321 kA/m, respectively, and the crystallization to Ln+Al2Ln+δ phases causes a ferromagnetic- to -paramagnetic phase transition. Thus, the hard magnetic properties are achieved only in the amorphous state.
AB - The amorphous phase in the Nd-Fe-Al and Pr-Fe-Al systems is formed in extremely wide composition ranges of 0 to 90 at% Fe and 0 to 93 at% Al by melt spinning. Ferromagnetic Ln90-xFexAl10 (Ln=Nd or Pr) bulk amorphous alloys with high coercive force at room temperature are obtained by a copper mold casting method. The maximum diameter of the cylindrical amorphous samples is 12 mm for the Nd-30%Fe-Al alloy and 3 mm for the Pr-30%Fe-Al alloys and decreases with deviating Fe content. Neither glass transition nor supercooled liquid region is observed in the temperature range before crystallization (T < Tx), which is different from other bulk amorphous alloys exhibiting wide supercooled liquid regions. The extremely high Tx/Tm and small ΔTm(=Tm-Tx) values are the reason for the achievement of large glass-forming ability in these systems. The bulk amorphous Ln60Fe30Al10 alloys are ferromagnetic with the Curie temperature (Tc) of 515 to 600 K which are much higher than those for Nd-Fe and Pr-Fe binary amorphous ribbons. The remanence (Br) and intrinsic coercive force (iHc) are 0.089 to 0.122 T and 277 to 321 kA/m, respectively, and the crystallization to Ln+Al2Ln+δ phases causes a ferromagnetic- to -paramagnetic phase transition. Thus, the hard magnetic properties are achieved only in the amorphous state.
KW - Bulk amorphous permanent magnet
KW - Copper mold casting
KW - Ferromagnetic bulk amorphous alloy
KW - Ferromagnetic cluster
KW - High coercive force
KW - High reduced glass transition temperature
KW - Large glass-forming ability
KW - Praseodymium-iron-aluminum alloy
UR - https://www.scopus.com/pages/publications/0000875532
M3 - 文章
AN - SCOPUS:0000875532
SN - 0040-8808
VL - 44
SP - 261
EP - 269
JO - Science Reports of the Rerearch Institutes Tohoku University Series A-Physics
JF - Science Reports of the Rerearch Institutes Tohoku University Series A-Physics
IS - 2
ER -