On the crystal structures of the R2Co17 intermetallic compounds

A contribution to the Sm–Co phase diagram

“…The Sm2Colv compound crystallizes in a hexagonal high-temperature modification [SmzColT(h)] of the disordered TbCuv-type and a rhombohedral lowtemperature modification [SmzCOlT(L)] of the Th2ZnlT-type (Khan, 1973). The crystal structure of Sm2COlT(h) is therefore neither of the Th2Nilv-type [reported by Buschow & Van der Goot (1968)] nor of the CaCustype [reported by Khan & Mfiller (1973)].…”

Effect of Nb and C additives on the microstructures and magnetic properties of rapidly solidified Sm–Co alloys

“…The unit cell parameters are related, with c 2:17 = 3c 1:5 and a 2:17 = (3a 1:5 ) ½ . In addition to the ordered Sm 2 Co 17 dumbbell structures, a disordered variant of the Th 2 Zn 17 -type structure is available which is TbCu 7 -type SmCo 7 structure where Sm and Co-Co dumbbell pairs randomly occupy the rare earth sites [2]. This metastable structure has the same unit cell as the CaCu 5 structure.…”

“…These properties have made Sm-Co as the ideal material in dynamic applications such as generators and motors, as well as in demanding environments. The Sm-Co system forms two related equilibrium phases in Corich compositions: the CaCu 5 -type SmCo 5 structure and the Th 2 Zn 17 -type Sm 2 Co 17 structure [1,2]. The unit cell parameters are related, with c 2:17 = 3c 1:5 and a 2:17 = (3a 1:5 ) ½ .…”

Magnetic properties of Sm2Fe17Ny with Al substituted for Fe

“…The R2Fe17 intermetallic compounds (R = rare earth) crystallize in the rhombohedral Th2Zn~v-type structure for the light R elements and in the hexagonal Th2Ni17-type structure for R heavier than Dy; both structure types may coexist for Gd, Tb and Dy [1,2]. The magnetic properties of the series have been investigated in great detail [3,4].…”