Effect of niobium on microstructure and magnetic properties of bulk anisotropic NdFeB/α-Fe nanocomposites

摘要

Bulk anisotropic NdFeB/α-Fe nano-composites were obtained directly from alloys of Nd_(11)Dy_(0.5-) Fe_(82.4-x)Nb_xB_(6.1) (x=0,0.5,1.0,1.5). High resolution transmission electron microscopy images showed the existence of Nb-rich amorphous grain boundary phase in the alloys with Nb doped. Field emission scanning electron microscope morphologies and X-ray diffraction patterns revealed the grain size and grain alignment of hot pressed and hot deformed nanocomposites. It was found that Nb could refine the grain size and grain texture in hot worked ribbons. Vibrating sample magnetometer results showed that the magnetic properties of the anisotropic nanocomposites were improved with increased Nb doping. The remanence, coercivity and maximum energy product of the bulk anisotropic Nd_(11)Dy_(0.5-) Fe_(80.4)Nb_2B_(6.1) nanocomposites were 1.04 T, 563 kA/m and 146kJ/m~3, respectively.