2003 Volume 50 Issue 1 Pages 50-57
Consolidation of Fe67Co95Nd3Dy0.5B20 glassy powders has been tried by uniaxial hot-pressing in the supercooled liquid state in order to synthesize a hard magnetic bulk material. Effects of hot-press temperature and powder size on the consolidation of the glassy powders were investigated. The powders sieved to 45 -90μm were heated up to temperatures in a range from 783 to 853 K under a pressure of 780 MPa. The glassy powders could be consolidated into bulk forms with relative densities above 99.0% by hot-pressing at 823 K and higher. The structure kept a glassy single phase for the compacts consolidated at 833 K and lower. These as-hot-pressed samples exhibited soft magnetic characteristics, but the soft magnetism changed to a hard type by annealing-induced crystallization. The remanence, coercivity and maximum energy product for the bulk compact consolidated at 833 K, followed by annealing for 600 s at 873 K were 1.03 T, 275 kA/m and 83.8 kJ/m3, respectively. The compact of the 90-150, um powders hotpressed at 833 K showed almost the same results as those made of the 45-90μm powder, while the density and magnetic properties were deduced for the compact of the powders sieved to under 45μm.
