Magnetic Properties and TEM Studies of Boron Enriched (Nd_0.95La_0.05)_9.5-11.5Fe_bal.Ti_2B_10.5 and (Nd_0.95La_0.05)_11Fe_bal.Ti_2Co0-15B_10.5 Ribbons

摘要

The magnetic properties and microstructures of rare earth lean and boron enriched (Nd_0.95La_0.05)_9.5-11.5Fe_bal.Ti_2B_10.5 and (Nd_0.95La_0.05)_11Fe_bal.Ti_2Co0-12.5B_10.5 melt spun ribbons have been investigated. Two magnetic phases, namely alpha-Fe and R_2Fe_14B, were found, by thermal magnetic analysis (TMA), in all the ribbons studied. High intrinsic coercivity (iHc) and maximum energy product ((BH)max) values in the range of 10 to 20 kOe and 14.3 to 16.8 MGOe respectively, have been achieved in (Nd_0.95La_0.05)_9.5-11.5Fe_bal.Ti_2B_10.5 nanocomposites, while the ribbons of (Nd_0.95La_0.05)_11Fe_76.5Ti_2B_10.5 exhibited the best combination of high iHc and (BH)max. Among (Nd_0.95La_0.05)_11Fe_bal.Ti_2Co0-12.5B_10.5 compositions studied, suitable Co-substitutions were found to be effective in increasing the Br and (BH)max, while keeping high vlaue of iHc. It was evidenced from transmission electron microscopy that the homogenity and fine grain size and high volume fraction of the R_2Fe_14B phase led to an increase in the iHc and maximum energy product of nanocomposites studied. The optimum magnetic properties of Br=9.4 kG, iHc=16.1 kOe and (BH)max=18.3 MGOe have been obtained on (Nd_0.95La_0.05)_11Fe_66.5Co_10Ti_2B_10.5 ribbons after an optimum treatment.