The Sm-Fe-V based 1:12 bulk magnets

A bulk magnet based on Sm-Fe-V with the ThMn12 crystal structure has been fabricated for the first time by hot-compaction of mechanically milled powders with a density of 92% of the theoretical density. The isotropic magnet exhibits a maximum coercivity of 1.06 T with a magnetization of 0.59 T, a remanent magnetization of 0.42 T and a (BH)(max) of 28 kJm(-3) at 3 T applied field. The Curie temperature is found to be 330 degrees C and the temperature coefficients of remanent magnetization and coercivity are 0.14% C-1 and 0.39% C-1, respectively. Minor hysteresis loops indicate a coercivity mechanism similar to that of the nanocrystalline Nd-Fe-B magnets. The isotropic magnet was hot-deformed up to 75% of its height, and the best magnetic properties obtained were M-mu 0(3T) = 0.63 M-mu 0(r)=0.45 T, H-mu 0(c)=0.88 T and (BH)(max)=33 kJm(-3). A small texture perpendicular to compaction direction was detected when the amount of vanadium was reduced, and the deformation temperature was increased from 800 to 1000 degrees C. (C) 2019 Elsevier B.V. All rights reserved.