Microstructure and magnetic properties of NdFeB alloys by co-doping alnico elements

Abstract Elements of alnico 8 are added into Nd-Fe-B alloys fabricated by rapid solidification method. It is observed that the magnetic properties at high temperature improved by small addition of alnico elements. The Curie temperature of the alloys increased from 580 K for standard alloy to 639 K by 20% addition of alnico 8 elements. The spin reorientation temperature decreased from 133 K to 104 K. The TEM analysis showed that elements of alnico 8 refine the microstructure of Nd-Fe-B ribbons. The STEM analysis confirmed the heterogeneous distribution of Nd, Fe, Cu, Al, Ni and homogeneous distribution of Ti, Nb and Co. The boundaries of nano grains contain more than 70% ferromagnetic elements, ensuring strong inter-grain coupling among the grains.