Effect of B addition on the microstructure and magnetic properties of melt-spun Sm12Co60-xFe19Cu6Zr3Bx (0 ≤ x ≤ 3) ribbons

The melt-spun Sm12Co60-xFe19Cu6Zr3Bx (0 ≤ x ≤ 3) ribbons were prepared using arc-melting method at a wheel speed of 20 m/s followed by annealing at different temperatures. The structural characterization showed that Sm12Co60-xFe19Cu6Zr3Bx (0 ≤ x ≤ 3) ribbons were mainly composed of TbCu7-type phase and α-Fe phase. The α-Fe phase in melt-spun ribbons was increased and the glass-forming ability (GFA) of Sm-Co matrix alloys was improved with the addition of B. The TbCu7-type phase in the ribbons annealed over 700 deg. C for 10 min was observed to decompose into Th2Zn17, CaCu5 and α-Fe type phases. The addition of higher B content resulted in decomposition of TbCu7-type phase more easily. Both coercivity and remanence were significantly affected by the B addition and annealing temperature. The Curie temperatures of amorphous Sm-Co phase, Sm(Co,M)5 and Sm2(Co,M)17 were found between 445 deg. C and 484 deg. C, 684 deg. C and 714 deg. C and 840 deg. C and 854 deg. C, respectively.