Title :
Fully dense bulk nanocomposites of (Sm1-xGdx)2(Co1-yFey)17+(Co, Fe) with high coercivity and high Curie temperature
Author :
Chen, Christina H. ; Lee, Don ; Liu, Sam ; Walmer, Michael H. ; Zhang, Yong ; Hadjipanayis, George C.
Author_Institution :
Univ. of Dayton, OH, USA
fDate :
7/1/2004 12:00:00 AM
Abstract :
Fully dense nanocomposites of (Sm1-xGdx)2(Co1-yFey)2:17 phase + Co/Fe were obtained by hot pressing the amorphous powders at 740°-760°C. Amorphous powders were made by mechanical alloying. Up to 14 kOe of Coercivity was obtained for these Cu and Zr free nanocomposites. X-ray diffraction patterns confirm the status of amorphous powder and crystallized structure after annealing at 750-825°C. Transmission electron microscopy image shows that the sizes of crystals were in the range of several nm to 100 nm. These fully dense nanocomposites have Curie temperatures higher than 900°C and lower temperature coefficient of magnetization, which would make them ideal candidates for temperature compensated permanent magnets.
Keywords :
Curie temperature; X-ray diffraction; amorphous magnetic materials; cobalt alloys; coercive force; gadolinium alloys; iron alloys; magnetic annealing; nanostructured materials; permanent magnets; pressing; samarium alloys; transmission electron microscopy; (Sm1-xGdx)2(Co1-yFey)17-(CoFe); 740 to 760 C; 750 to 825 C; Curie temperature; X-ray diffraction patterns; amorphous powders; annealing; coercivity; crystal size; crystallized structure; hot pressing; mechanical alloying; nanocomposites magnets; permanent magnets; rare earth magnets; transmission electron microscopy; Alloying; Amorphous materials; Coercive force; Crystallization; Iron; Nanocomposites; Powders; Pressing; Temperature; Zirconium; Curie temperature; Sm–Co rare earth magnets; full density; nanocomposites magnets; temperature coefficient;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2004.830398
