Volume production of Nd2Fe14B + Fe3B nanocomposite powders and their magnetic properties in terms of exchange coupling

The present study reports the magnetic properties of the Nd4Fe77.5B18.5 compound in term of exchange coupling between Nd2Fe14B and Fe3B magnetic nanocrystals in melt spun powders made by varying the quenching speed. Those magnetic properties were characterized as functions of nanocrystal size and volume fraction of each magnetic phase which was possible by employing Henkel plots (δM) and refined Mössbauer spectroscopy. The optimized magnetic properties obtained from the present volume production line were Br = 11.73 kG, iHc = 3.082 kOe, and (BH)max = 12.28 MGOe. The volume fraction of each magnetic phase for those conditions giving the grain size of 10 nm were α‐Fe: 4.2%, Fe3B: 60.1%, and Nd2Fe14B: 35.7%. The superior magnetic properties in the Nd2Fe14B + Fe3B based nanocomposites were confirmed to be dependant on the volume fraction of Fe3B. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)