Nd2Fe14B-based nanocomposite magnets with transition metal and carbon additions

Nanocomposite intermediate rare-earth/high-boron content hard magnetic alloys, having compositions Nd9Fe73B12.6C1.4M4 (M=Ti, V, Cr, Zr, or Nb), have been produced as melt spun ribbon. As for the Ti addition, all the other solutes were effective in modifying the crystallization behavior so that the Nd2Fe14B phase formed rather than the cubic Nd2Fe23B3 phase. The magnetic properties of the V-, Cr-, Zr-, and Nb-containing alloys in the as-spun state and following annealing are compared with those of the Ti-containing alloy. Good combinations of intrinsic coercivity (1020 kA m(-1)) and of maximum energy product (97 kJ m(-3)) were obtained for the V-containing alloy, closely comparable with those for the M=Ti alloy, and the Zr addition also yielded a good property combination. (C) 2006 American Institute of Physics.