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Ce-Fe-B rare-earth alloys are alternative to substitute partially for Nd-Fe-B permanent magnets for reducing the cost and the balance use of rare-earth elements. However, coercivity is rather low in Ce-Fe-B magnets, which partially ascribes to the instability of Ce 2 Fe 14 B phase and the low magnetocrystalline anisotropy. In this paper, magnetic properties are investigated in Ce 13-x Gd x Fe 81 B 6 ribbons via substituting of Gd for Ce. X-ray diffraction shows that a little amount of Gd substitution for Ce leads to an increase in the intensity of diffraction peak for main phase, which should be attributed to the improvement of the stability of R 2 Fe 14 B phase and the reduction in the amount of amorphous phase. Even though the magnetocrystalline anisotropy is lower in Gd 2 Fe 14 B than that in Ce 2 Fe 14 B, the coercivity increases to 5.88 kOe for a little amount of Gd substitution in Ce 12 Gd 1 Fe 81 B 6 ribbons. For Gd atomic percent more than 3% the coercivity decreases, and the remanence drops significantly. With the increase of Gd atomic percent, Curie temperature increases monotonically. Henkel plots indicate that Gd substitution for Ce could enhance the effect of exchange coupling, which owes to the increase of exchange coefficient in main phase as well as to the reduction in the amount of amorphous phase. These investigations show that a little amount substitution of Gd is beneficial to improve the magnetic properties without a significant drop of the remanence. [ABSTRACT FROM AUTHOR]

A series of misch-metal (MM = 28.27 wt % La, 50.46 wt % Ce, 5.22 wt % Pr, 15.66 wt % Nd)-iron-boron isotropic ribbons with atomic formula (MM) 12+x Fe 82-x-y B 6+y (x = 0, 1, 2, 3, 4, y = 0, 0.5, 1, 1.5, 2) are prepared by melt spinning technique. A large energy product ( BH ) max of 12 MGOe is obtained with the composition of MM 13 Fe 81 B 6 at optimized processing. The ribbons with both coercivity larger than 10 kOe and ( BH ) max larger than 10 MGOe are achieved in a wide composition range. All the samples exhibit the tetragonal crystal structure. The magnetization and Henkel plot (δ M ) measurements indicate that the ribbons have a relatively homogeneous microstructure and strong exchange-coupling interactions. The average grain size of the ribbons is around 30 nm determined via Scherrer's formula. Meanwhile, the transmission electron microscope (TEM) image also verifies that the ribbons have a homogeneous nanoscale microstructure. In addition, the spin reorientation temperature T sr is investigated by ac susceptibility χ ac measurement. [ABSTRACT FROM AUTHOR]