Research on preparing compact bulk nanocomposite Nd2Fe14B/α-Fe magnetic materials by hot extrusion

In this paper, compact bulk nanocomposite Nd2Fe14B/alpha-Fe magnetic materials were prepared by hot extrusion of amorphous and nanocrystalline powders, which were prepared by high-energy ball-milling (HEBM) of the Nd2Fe14 B-type hard magnetic phase with 20 vol% of alpha-Fe as soft magnetic phase. The extrusion temperature has important influence on magnetic properties and microstructure of magnetic materials. The results show that the grain size of Nd2Fe14B and alpha-Fe phase increases steadily with increasing extrusion temperature. Furthermore, optimal extrusion temperature of 1223 K occurs, at which the highest magnetic properties and relative density can be obtained. (C) 2006 Elsevier B.V. All rights reserved.