HIGH-COERCIVITY (NDDY)(2)(FENB)(14)B-ALPHA-FE NANOCRYSTALLINE ALLOYS

High coercivity, high remanence, and high energy product (NdDy)(2)(FeN b)(14)B-alpha-Fe nanocrystalline alloys containing 0 to 30 wt % alpha- Fe have been prepared by melt spinning and subsequent annealing. The b est magnetic properties of remanence (B-r), coercivity (H-ci), and max imum energy product [(BH)(max)] are 1.02 T, 702 kA/m, and 134 kJ/m(3), respectively, for Nd8.16Dy1Fe85.26Nb1B4.58. The microstructure consis ts of a two phase nanocomposite of hard magnetic (NdDy)(2)(FeNb)(14)B and soft magnetic alpha-Fe with an average size of about 30 nm. These small dimensions allow effective exchange coupling between hard and so ft magnetic grains and result in the simultaneous enhancement of B-r, H-ci, and (BH)(max). A systematic study on the effect of annealing tem perature and time on the microstructure and magnetic properties has be en carried out. (C) 1997 American Institute of Physics.