Phase evolution and magnetic metals co-substituted studies of La and refractory co-substituted alpha i-Fe/R2Fe14B-type nanocomposites

Phase evolution and magnetic properties of (Nd0.95La0.05)(9.5 similar to 11)Febal.M2B10.5, where M=Cr, Ti, Mb, V, Mo, Zr, Hf, Ta, Mn or W, melt spun ribbons have been investigated. Almost all the alloy ribbons, except for (Nd0.95La0.05)(9.5)Fe78M2B10.5 (M=Mo and Mn), consist merely two magnetic phases, namely alpha-Fe and R2Fe14B, which display a better combination of H-i(c) and magnetic energy product. Remanence (B-r) and coercivity (H-i(c)) values in the range of 8.0 to 9.1 kG and 9.5 to 18.9 kOe, respectively, can be achieved. Among compositions studied, the Ti and W-substitutions were found to be most effective in increasing the Br and H-i(c), respectively. For a fixed refractory metal substitution, namely, M=Cr, Ti or Mb, an increase in the total rare earth concentration resulted in nanocomposites of small grain sizes and a high volume fraction of the R2Fe14B phase, leading to an increase in the magnetic properties.