부산대학교 도서관

Magnetic properties of melt spun LaCo.sub.5-based ribbons are remarkably improved by phase modification and grain refinement with M (M = Ti, Zr and Hf) substitution for Co in LaCo.sub.5 and R (R = Ce, Pr, Nd, Sm, and Y) substitution for La in La Co.sub.4.7C.sub.0.3, respectively. Because of the coexistence of considerable amount (~ 42-70 vol%) of soft magnetic La.sub.2Co.sub.7 (2:7) and LaCo.sub.13 (1:13) phases with LaCo.sub.5 (1:5) phase, small coercivity (.sub.iH.sub.c) of 0.8 kOe and 0.3 kOe are found in LaCo.sub.5 and LaCo.sub.4.7C.sub.0.3 ribbons, respectively. A slight Ti, Zr, or Hf substitution for Co in LaCo.sub.4.9M.sub.0.1 ribbons is helpful to effectively decrease the amount of soft magnetic phases (down to ~ 3.1-5.6%) and refine the grain size of 1:5 phase, and therefore improves the .sub.iH.sub.c and the squareness of demagnetization curve. .sub.iH.sub.c of the ribbons is significantly improved to 8.1-11.6 kOe. On the other hand, R substitution for La in La.sub.1-xR.sub.xCo.sub.4.7C.sub.0.3 ribbons is also effective in obtaining large amount of 1:5 phase (82.8-86.2 and 90.8-97.5% for x = 0.25 and 0.5, respectively). R entrance into 1:5 phase modifies the magnetization, magnetocrystalline anisotropy field, and Curie temperature, simultaneously. In addition to large amount 1:5 phase, fine size of the grains for La.sub.1-xR.sub.xCo.sub.4.7C.sub.0.3 samples related to C-doping also contribute to enhance magnetic properties, especially large .sub.iH.sub.c and good squareness of demagnetization curve. Magnetic properties of La.sub.1-xR.sub.xCo.sub.4.7C.sub.0.3 ribbons are mainly dominated by their corresponding phase constitutions and the magnetically intrinsic properties of RCo.sub.5 phase. Accordingly, we attain the attractive magnetic properties of .sub.iH.sub.c = 15.1 kOe and (BH).sub.max = 3.8 MGOe for La.sub.0.5Ce.sub.0.5Co.sub.4.7C.sub.0.3; .sub.iH.sub.c = 10.3 kOe and (BH).sub.max = 4.4 MGOe for La.sub.0.5Y.sub.0.5Co.sub.4.7C.sub.0.3 and .sub.iH.sub.c = 15.8 kOe and (BH).sub.max = 5.2 MGOe for La.sub.0.5Sm.sub.0.5Co.sub.4.7C.sub.0.3, respectively. This study provides the effective way to improve magnetic properties of isotropic melt spun LaCo.sub.5-based ribbons by phase modification and grain refinement. Graphical abstract
Author(s): H. W. Chang [sup.1], Y. M. Guo [sup.1], Y. H. Fang [sup.1], W. C. Chang [sup.1], C. C. Shaw [sup.2] Author Affiliations: (1) grid.412047.4, 0000 0004 0532 3650, Department [...]