Effects of Zr and Nb dopants on the microstructure and magnetic properties of Nd₂Fe₁₄B/α-Fe nanocomposite ribbons

ABSTRACT The effects of Zr and Nb dopants on the microstructure and magnetic properties of exchangecoupling nanocomposite Nd_8.60Fe_80.80Cu_0.3Zr_2-xNb_xB_8.30(x=0,1,2) ribbons were systematically studied. It is found that both Zr and Nb dopants can suppress the magnetic grain growth efficiently. The combination of Zr and B consumes partial B and induces to the reduction N₂Fe₁₄B phases. Comparing to the effect of Zr addition, Nb addition can improve the squareness of the hysteresis loop and suppress the magnetic grain growth more effectively. The optimum magnetic properties were found in the annealed Nd_8.60Fe_{8 0.80}Cu_0.3Nb₂B_8.30 ribbons as the following: Br=0.89T,H_ci=479.1kA·m^-1,(BH)_max=107.4kJ·m^-3.