Enhanced magnetic properties in Zr-containing rare earth-rich Didymium (Nd/Pr)-based nanocrystalline hard magnetic alloys

摘要

A systematic study of the influence of processing conditions and Zr addition on the magnetic properties of RE-n.ch Didymium (Nd/Pr)_(14)Fe_(80)B_6 (Nd:Pr ratio of 3:1) is reported. For directly quenched alloys. various roll speeds resulted in grain sizes d_g within the range 35-50nm. Increasing remanence J_r and maximum energy product (BH)_(max) values were observed as d_g decreased (up to 0.86T and up to 124kJ/m~3, respectively). Small Zr addition (1 at. percent) resulted in improved J_r and (BH)_(max) (up to 0.92 T and up to 142 kJ/m~3 respectively). For overquenched and annealed alloys. partial substitution of Fe by Zr (0-4 at. percent) indicated a marked dependence of the magnetic properties on Zr content with an excellent combination of J_r (1.0 T). _iH_c (1574 kA/m) and (BH)_(max) (149 kJ/m~3) at 2 at. percent Zr, Results are interpreted in terms of variations in the scale of the nanostructure and of the effects of Zr substitutions into the 2/14/1 unit cell.