Nanostructured melt-spun Sm(Co-Fe-Zr-B)/sub 7.5/ alloys for high temperature magnets

In this paper, we report high coercivity in as spun and annealed ribbons of Cu free Sm(Co/sub bal/Fe/sub z/Zr/sub y/B/sub x/)/sub 7.5/ samples, with varying B, Zr and Fe content (x-0.005-0.06, y=0.02-0.16, z=0.08-0.3) were studied. Also TEM studies have been used to investigate microstructure and grain size distribution. Average grain size is 30-50 nm is as spun ribbons and 70 to 100 nm for annealed ribbons. The grain distribution is very uniform in the scale of nanometers for the samples with square loop. Very good loop squareness and a maximum energy product of (BH)/sub max/=10.7 MGOe has been obtained at RT for sample with composition Sm(Co/sub bal/Fe/sub 0.3/Zr/sub 0.02/B/sub 0.04/)/sub 7.5/ after annealing at 600/spl deg/C for 75 min.