Microstructural Characterization of Novel Ni-Containing Nd-Fe-B Strips by Strip Casting

The characteristics of novel Nd-Fe(Ni, Co, Al)-B microstructure prepared by strip casting technique were studied. The novel microstructure was observed using scanning electron microscope (SEM) and transmission electron microscope (TEM). Along the direction of heat flow, there are two kinds of different microstructures. Close to the wheel side, there is a thick layer containing many polygonal Nd2Fe14B grains. Near the free surface side, however, there are relative uniform platelike Nd2Fe14B grains whose growth direction is not completely the direction of the heat flow during solidification. The formation of the novel microstructure is presumed to be the contribution of the special temperature field and Ni component.