The dependence of magnetic properties and hot workability of rare earth-iron-boride magnets upon composition

Hot deformed magnets can be commercially produced from hyper-stoichiometric nanocrystalline Nd-Fe-B compositions. This paper summarizes the influence of the rare-earth component (Nd, Pr, Dy) and gallium to magnetic properties and hot workability of die-upset magnets based upon hyper-stoichiometric compositions. Increasing the Nd from 13.3 to 14.4 at.% raises the H_ci from 770 to 930 kAm^-1. B_r values are highest (1.31 T) at lower levels of RE (∼13 at.%), although such compositions exhibit a decrease in hot workability. The substitution of Dy and Pr for Nd promotes higher H_ci values at some expense in B_r. Gallium additions up to 0.5 at.% significantly increase both B_r and H_ci.