Magnetic properties and microstructure of nanocomposite (La, Pr)₃Fe₁₄B ribbons by doping la element

The research on the mixed rare earth-iron based permanent magnet compounds by doping rare earth elements in Nd-Fe-B or Pr-Fe-B permanent magnet has been a hot topic in recent years. In this paper, La doped Pr-Fe-B ((La_xPr_1-x)₃Fe₁₄B, x=0, 0.3, 0.6, (La, Pr)-Fe-B) ribbons were prepared by vacuum arc melting technique and subsequently melt-spinning method at the optimal quenching speed. The microstructure, phase distribution and magnetic properties of the nanocomposite magnets were investigated. It is found that the samples present 2:14:1 main phase, La₂O₃ phase and minor α-Fe phase. No excess amorphous phase is observed, indicating that 20 m/s is an optimization of preparation condition to fabricate the (La, Pr)-Fe-B ribbons in this work. The EBSD results reveal that La-rich phases distribute mostly over the grain boundary. The substitution of La for Pr in Pr-Fe-B has some influence on the coercivity, but little on the saturation magnetization. This is thought to be related with the agglomeration of rare earth-rich intermetallic phase. We hope that this work can provide new ideas in the exploration of mixed rare earth-iron based permanent magnet compounds, which possess a cost advantage and a promising potential for practical applications.