Title :
Nanostructured melt-spun Sm(Co,Fe,Zr,B)7.5 alloys for high-temperature magnets
Author :
Makridis, Sofoklis S. ; Litsardakis, George ; Efthimiadis, Kostas G. ; Papathanasiou, George ; Panagiotopoulos, Ioannis ; Hofinger, Sabine ; Fidler, Josef ; Hadjipanayis, George C. ; Niarchos, Dimitris
Author_Institution :
Dept. of Electr. & Comput. Eng., Aristotle Univ., Thessaloniki, Greece
Abstract :
High coercivity, the highest for Cu-free 2 : 17 Sm-Co ribbons, has been obtained in as-spun (Hc=21.1 kOe) and short time annealed (Hc=23.2 kOe) samples of Sm(CobalFezZryBx)7.5 alloys, with varying B, Zr, and Fe content (x = 0-0.06, y=0-0.16, z = 0.08-0.3) and wheel speed. In as-spun samples, the TbCu7 type structure and in annealed samples the Th2Zn17 and CaCu5 type structures is observed, plus fcc Co as minority phase is observed. Reduced remanence (Mr/Ms) is higher than 0.7. High-temperature magnetic measurements show very good stability above 300°C with coercive field as high as 5.2 kOe at 330°C. For annealed Sm(CobalFe0.3Zr0.02B0.04)7.5, very good loop squareness and high maximum energy product of 10.7 MGOe have been obtained. Increasing Zr content results in less uniform microstructure of annealed ribbons.
Keywords :
boron alloys; cobalt alloys; coercive force; crystal microstructure; ferromagnetic materials; ferromagnetic-antiferromagnetic transitions; iron alloys; magnetic annealing; magnetic hysteresis; melt spinning; nanostructured materials; permanent magnets; remanence; samarium alloys; zirconium alloys; 300 degC; 330 degC; Sm(CoFeZrB)7.5; coercive field; coercivity; high maximum energy product; high-temperature magnets; microstructure; nanostructured melt-spun Sm(Co,Fe,Zr,B)7.5 alloys; remanence; short time annealed; very good loop squareness; very good stability; wheel speed; Annealing; Coercive force; Iron alloys; Magnetic variables measurement; Microstructure; Remanence; Stability; Wheels; Zinc; Zirconium;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2003.815731
