Highly coercive milled and melt-spun (Pr,Nd)FeB-type magnets and their hot workability

Highly coercive isotropic (Pr/sub 1-x/Nd/sub x/)/sub 2/Fe/sub 14/B-type magnets (0/spl les//spl times//spl les/1) have been processed using high energy ball milling and melt-spinning techniques, and an assessment of their hot deformation behavior has been carried out. A very high coercivity of /spl mu//sub 0/H/sub c/=2.7 T and a remanence of J/sub r/=0.72 T were found after annealing partly amorphous Pr/sub 15/DyFe/sub 75.9/B/sub 8/Zr/sub 0.1/ ribbons. Samples containing Dy (1at.%) and Zr (0.1 at.%) exhibit an improved stability against grain growth with increasing the annealing temperature. It has been found that the deformation forces necessary for texturing by hot deformation are the lowest for the as-milled Pr-containing alloys. As-milled Pr/sub 15/Fe/sub 77/B has been textured by die-upsetting at 750/spl deg/C obtaining magnetic properties as high as J/sub r/=1.27 T, /spl mu//sub 0/H/sub c/=1.20 T and (BH)/sub max/=307 kJ/m/sup 3/.