PhaseEvolutionandMagneticStudiesofLaandRefractoryMetalsCo-substitutedα-Fe/R2Fe14B-typeNanocomposites

Phase evolution and magnetic properties of （Nd_o.95La0.05）9.5-11Febal.M2B10.5. where M=Cr, Ti, Nb, V, Mo, Zr, Hf, Ta, Mn or W, melt spun ribbons have been investigated. Almost all the alloy ribbons. except for（Nd0.95La0.05）9.5Fe78M2B10.5（M=Mo and Mn）,consist merely two magnetic phases, namely α-Fe and R2Fe14B, which display a better combination of iHc and magnetic energy product. Remanence （Br） and coercivity （iHc） 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 iHc, respectively. For a fixed refractory metal substitution, namely, M=Cr, Ti or Nb, 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.