Nd-Fe-B alloys containing NdAu nano particles

Melt-spun ribbons of Nd-Fe-B modified with Au and/or Cu have been investigated as a function of both composition and cooling rate. When added to stochiometric Nd2Fe14B (2-14-1), Au resulted in the formation of NdAu at the expense of the 2-14-1 phase. The addition of Nd(Au1-xCux) to the stochiometric material (Nd2Fe14B)(95) + Nd-2.5 (Au1-xCux)(2.5) (x = 0-0.3) results in a novel two phase microstructure. As spun alloys solidified at higher wheel speeds (greater than or equal to 25 m/s) contain a two-phase structure consisting of an amorphous Nd-Fe-B matrix with embedded Nd(Au1-xCux) nanophase spheres. The structure of nanocrystalline particles has been characterized with X-ray diffraction, electron microdiffraction and energy dispersive spectroscopy. The formation mechanism of this novel structure evolution under different compositions and processing parameters is discussed. (C) 2000 Elsevier Science S.A. All rights reserved.