Fully Dense Bulk Nanocomposites of (Sm<tex>$_1-rm x$</tex>Gd<tex>$_rm x$</tex>)<tex>$_2$</tex>(Co<tex>$_1-rm y$</tex>Fe<tex>$_rm y$</tex>)<tex>$_17+!!!$</tex>(Co, Fe) With High Coercivity and High Curie Temperature

Abstract

Fully dense nanocomposites of (Sm/sub 1-x/Gd/sub x/)/sub 2/(Co/sub 1-y/Fe/sub y/)/sub 2:17/ phase + Co/Fe were obtained by hot pressing the amorphous powders at 740/spl deg/-760/spl deg/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/spl deg/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/spl deg/C and lower temperature coefficient of magnetization, which would make them ideal candidates for temperature compensated permanent magnets.