Microstructures and the Magnetic Properties of Fe₃B/(Nd, Dy)₂Fe₁₄B Nanocomposite Microalloyed with Cu and Zr

Abstract

The effect of Zr and Cu addition to a Nd_3.4Dy₁Fe_72.3B_18.5Cr_2.4Co_2.4 alloy on the microstructure and the magnetic properties of Fe₃B/Nd₂Fe₁₄B nanocomposite has been investigated by a three-dimensional atom probe (3DAP) and transmission electron microscopy (TEM). Addition of a small amount of Zr and/or Cu is effective in improving the hard magnetic properties of the base alloy. Cu atoms form clusters in the early stage of crystallization, and Zr atoms are segregated at the interfaces of Fe₃B/Nd₂Fe₁₄B being rejected from the Fe₃B soft magnetic phase on the optimal heat-treated condition. This causes refining the nanocomposite microstructure, resulting in improved hard magnetic properties compared to those of the base alloy.