Author :
Chang, W.C. ; Wang, S.H. ; Chang, S.J. ; Tsai, M.Y. ; Ma, B.M.
Abstract :
The phase transformations and magnetic properties of rare earth lean and boron rich (Nd0.95La0.05)xFe bal.M2B10.5, where x=9.5 or 11 and M=Cr, Ti, Nb, V, Mo, Zr, Nf, Ta, Mn or W, melt spun ribbons have been investigated. Two magnetic phases, namely α-Fe and R2Fe 14B, were found in ribbons studied. A third magnetic phase, the R2Fe23B3, was also detected in (Nd 0.95La0.05)9.5Fe78M2 B10.5 (M=Mo and Mn). Remanence (Br) and coercivity (iHc) values in the range of 8.0 to 9.1 kG and 9.5 to 18.9 kOe, respectively, have been achieved in nanocomposites with merely two magnetic phases. 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 R 2Fe14B phase. The combination of fine grain size and high volume fraction of R2Fe14B phase led to an increase in the iHc and maximum energy product, (BH)max of nanocomposites studied. A Br of 9.1 kG, iHc of 16.7 kOe and (BH)max of 16.8 MGOe have been obtained on (Nd0.95La0.05)11 Fe76.5Ti2B10.5
Keywords :
alloying additions; boron alloys; coercive force; composite materials; ferromagnetic materials; grain size; iron alloys; nanostructured materials; neodymium alloys; permanent magnets; rare earth alloys; remanence; α-Fe; α-Fe/R2Fe14B-type nanocomposites; (Nd0.95La0.05)11Fe76.5 Ti2B10.5; (Nd0.95La0.05)9.5Fe78 M2B10.5; R2Fe14B; R2Fe23B3; coercivity; fixed refractory metal substitution; grain sizes; magnetic phases; magnetic properties; maximum energy product; melt spun ribbons; phase transformations; refractory metals effects; remanence; Boron; Grain size; Iron; Magnetic properties; Nanocomposites; Neodymium; Niobium; Phase detection; Remanence; Zirconium;
