Phase composition, structure and magnetic behaviour of low neodymium Nd-Fe-B permanent magnets

Phase composition, structure and magnetic behaviour of two low neodymium hard magnetic materials differing in way of preparation, centrifugal atomization and melt spinning, were compared using Mössbauer spectroscopy, X-ray diffraction, thermomagnetic analysis and SQUID magnetic measurements. Better hard magnetic characteristics of the melt-spun material are explained on the basis of the differences in content of surface and/or interface Fe(Nd, B) phases. Their remarkable presence in the centrifugally atomized material lowers the content of Fe3B, Fe2B, α-Fe, and Nd2Fe14B phases that are responsible for the magnetic qualities of the material. There are just subtle differences in the phase composition of both materials after thermomagnetic measurement, where the a-Fe phase prevails as a product of thermal decomposition