ENHANCEMENT OF MAGNETIC-PROPERTIES OF SM(FE, CO, TI)12 MELT-SPUN RIBBONS BY REFINING CRYSTALLIZED GRAINS

Present works describe the improvement of the magnetic properties of Sm(Fe, Ti)12 melt-spun ribbons with ThMn12- type structure. In order to increase the remanence, the Ti content was decreased and the heat treatment temperature and time were lowered and shortened, respectively. As a result, the maximum energy products increases. The (BH)max of 56.8 kJm-3 (7.1 MGOe) was obtained with SmFe11.25Ti0.75 melt-spun ribbons annealed at 770-degrees-C for 10 min. This is the highest energy products among reported values on melt-spun ribbons in ternary Sm-Fe-Ti system so far. The Co addition is effective for increasing the saturation magnetization. Sm(Fe0.8Co0.2)11.25Ti0.75 melt-spun ribbon exhibits the high maximum energy products of 67.2 kJm-3 (8.4 MGOe) after annealing at 800-degrees-C for 10 min. Microstructural studies indicate that the ribbons consist of fine grains which have the average grain diameter of nearly 40 nm.