Magnetic Properties and Phase Transformation of Sm-Fe-Co-X (X = Ga, V, B, Si, and Ti) Permanent Magnetic Materials

The magnetic properties and phase transformation of Sm(Fe 0.8 Co 0.2 ) 11 X (X = Ga, V, B, Si, and Ti) were investigated. The Sm(Fe 0.8 Co 0.2 ) 11 X ribbons were produced by rapid solidification process, and their phase transformation and magnetic properties were analyzed using DSC and VSM. It was confirmed that the melt-spun amorphous phase was converted to the ɑ-Fe phase, then to TbCu 7 -type phases, and finally to the ThMn 12 -type phase. Magnetic property measurements show that the coercivities of the Sm(Fe 0.8 Co 0.2 ) 11 X ribbons vary with the compositions. The Ti substituted sample has the highest concentration of ThMn 12 -type phase across all annealing temperatures and the corresponding coercivity is also the highest among the samples. The squareness, M r /M s , of the samples shows that the trends follow the degree of crystallinity of the ThMn 12 -type phase, so that higher concentrations of hard magnetic phase result in the enhanced squareness.