Application of a Dy₃Co_0.6Cu_0.4H _x Addition for Controlling the Microstructure and Magnetic Properties of Sintered Nd-Fe-B Magnets

The focus of new technologies on the formation of inhomogeneous distributions of heavy rare-earth metals (REMs) in hard magnetic Nd-Fe-B materials is of scientific importance to increase their functional properties, along with preserving existing sources of heavy REMs. This paper focused on the coercivity enhancement of Nd₂Fe₁₄B-based magnets by optimizing the microstructure, which includes the processes of grain boundary structuring via the application of a Dy₃Co_0.6Cu_0.4H_x alloy added to the initial Nd-Fe-B-based powder mixtures in the course of their mechanical activation. We have studied the role of alloying elements in the formation of phase composition, microstructure, the fine structure of grains, and the hysteretic properties of hard magnetic Nd(R)₂Fe₁₄B-based materials. It was shown that the Dy introduction via the two-component blending process (the hydrogenated Dy₃Co_0.6Cu_0.4 compound is added to a powder mixture) resulted in the formation of the core-shell structure of 2-14-1 phase grains. The efficient improvement of the coercivity of Nd(RE)-Fe-B magnets, with a slight sacrifice of remanence, was demonstrated.