Magnetic properties and phase evolution of nanocomposite Nd10Febal.MCB10.5 (M = Ti, Nb, V, Cr and Mo) melt-spun ribbons

The magnetic properties and the phase evolution of boron enriched Nd10Febal.MCB10.5 (M = Ti, Nb, V, Cr and Mo) melt-spun ribbons have been investigated. For M = Ti, V, Cr and Mo. The main phases in the ribbons are Nd(2)Fe(14)A FC3B and alpha-Fe, while the metastable Fe3B phase is suppressed for the alloy ribbons with M = Nb. Among them, the alloy ribbons with M = Ti and Nb exhibit the best magnetic properties and the highest coercivity: B-r = 9.2 kG, H-i(c) = 12.1 kOe and (BH)(max) = 16.2 MGOe and B-r = 8.5 kG, H-i(c) = 15 kOe and (BH)(max) = 14.5 MGOe, respectively. The high remanence of the M = Ti compound mainly results from the exchange coupling effect between the magnetically soft Fe3B phase and the hard Nd2Fe14B phase. The high coercivity of the M = Nb compound is due to the existence of a large volume fraction of the Nd2Fe14B phase in the matrix. (C) 2002 Elsevier Science B.V. All rights reserved.