MODELING OF MAGNETIC-PROPERTIES OF ND-DY-FE-B PARTICULATE COMPOSITES WITH DIFFERENT COMPACTING PROCESSES

Nd-Fe-B hard magnetic materials have been investigated intensively in recent years because of their high coercivities and maximum energy pro ducts. In this study we have examined tl-le properties of the quaterna ry alloy Nd-Dy-Fe-B. Experiments revealed the underlying magnetic prop erties of these samples and these have been related to a theoretical m odel of the magnetization process. Samples were prepared in the form o f particles either in the free state, in a randomly oriented state or in a field-oriented state obtained from solidification under an extern al field. Modeling results and microstructure analysis showed that com pacting process strongly influenced the final magnetic properties thro ugh the change in the coupling coefficient resulting from one- or two- dimensional couplings among the particles which were totally different from those of the same materials in bulk state. (C) 1998 Elsevier Sci ence B.V. All rights reserved.