Journal of Magnetism and Magnetic Materials 258–259 (2003) 586–589 Structure and magnetic properties of nanocrystalline alloys based on Nd2Fe14B obtained by various techniques

In the present work a study of phase composition and structure parameters influence on the magnetic properties of nanocrystalline Nd–Fe–B alloys was carried out. The alloys studied were produced by various techniques such as a centrifugal spraying method, melt spinning and hydrogenation disproportionation desorption recombination (HDDR) process. The alloys produced by centrifugal spraying were found to be multi-phase and contained, along with the Nd2Fe14B phase, particles of a-Fe and Nd-rich phase. A decrease of crystallite sizes of the magnetic phases (Nd2Fe14B and a-Fe) and reduction of the a-Fe amount has led to the magnetic properties refinement. The melt-spun single-phase alloy was characterized by finer crystallites and higher magnetic properties. HDDR processed alloys contained crystallites with sizes in the range of 50–100 nm, which were higher than those in the rapidly solidified alloys (25–50 nm). The HDDR processed alloys had sufficiently high coercive force, but their remanence was lower than that in the rapidly solidified powders