THE MAGNETIC-PROPERTIES OF ND-FE-B MAGNETS PRODUCED BY LIQUID DYNAMIC COMPACTION

Several Nd-Fe-B magnets were prepared by the liquid dynamic compaction (LDC) process, one of the newer rapid solidification techniques. The LDC processed magnets, when produced at low-atomization gas pressures (coarse spray and low cooling rates), showed a dendritic structure and showed a mostly amorphous structure when produced at high gas pressures (fine spray and high cooling rates). Low coercivity values, less than 1 kOe, were found for the mostly amorphous magnets. Subsequent heat treatment of the latter magnets dramatically improved the magnetic properties, particularly the coercivity, up to 15.6 kOe. Energy products as high as 10 MGOe were obtained after selected heat treatments. The magnets produced by LDC were magnetically isotropic as is the case for melt-spun ribbons and hot-pressed magnets.