PERMANENT-MAGNETS PREPARED FROM SM10.5FE88.5ZR1.0NY WITHOUT HOMOGENIZATION

In as-cast Sm2Fe17 the high amount of alpha-Fe caused by a peritectic reaction can be considerably reduced by a small addition of about 1 at % Zr. X-ray diffraction showed that as-cast Sm10.5Fe88.5Zr1.0 mainly c onsists of a phase with the Th2Zn17-type structure and SmFe3. Non-homo genized Sm10.5Fe88.5Zr1.0 was milled and (i) annealed in vacuum or (ii ) treated with a nation-disproportionation-desorption-recombination (H DDR) process. The annealed and subsequently nitrogenated powder is mag netically anisotropic and has a coercivity mu(OJ)H(C) up to 2.0 T and an energy product (BH)(max) up to 136 kJ/m(3). HDDR-treated and nitrog enated powder is isotropic and exhibits values of mu(OJ)H(C) = 3.1 T a nd (BH)(max) = 103 kJ/m(3). Consequently, Sm10.5Fe88.5Zr1.0Ny (y appro ximate to 16) permanent magnets with very good properties can be prepa red without the time-consuming homogenization procedure.