A new Sm(Co,Fe,Cu)4B/Sm2(Co,Fe,Cu)7 cell structure with the coercivity of up to 5.01 T

A new Sm(Co,Fe,Cu)(4)B/Sm-2(Co,Fe,Cu)(7) cell structure is found, and its phase composition, microstructure and magnetic properties are investigated. Particularly, the atom structure of main phase is analyzed by extended X-ray absorption fine structure. It was found that as-spun SmCo2.94FeCu0.06B ribbons were composed of amorphous phase and approximate equiaxed Sm(Co,Fe,Cu)(4)B nanocrystallines. The high disorder of the nanocrystallines leads to the low magnetic anisotropy. After the as-spun ribbons were annealed at 800 degrees C for 30 min, the amorphous phase disappeared completely. The short rod-shaped Sm (Co,Fe,Cu)(4)B grains have a staggered distribution accompanied by similar to 8 vol% lamellar Sm-2(Co,Fe,Cu)(7) phase at grain boundaries, and the new cell/cell-wall-type Sm(Co,Fe,Cu)(4)B/Sm-2(Co, Fe, Cu)(7) microstructure is produced. The annealed ribbons show an ultra-high coercivity of up to 5.01 T at room temperature, 40.64 T at 5 K (obtained by extrapolating), and estimated to be similar to 41.96 T at 0 K. The microstructureal models of both ribbons are created and the coercivity mechanism is discussed in detail. (C) 2018 Elsevier B.V. All rights reserved.