Effect of Dy Addition on the Magnetic and Mechanical Properties of Sintered Nd–Fe–B Magnets Prepared by Double-Alloy Powder Mixed Method

The effect of Dy addition on the magnetic and mechanical properties of sintered Nd-Fe-B magnets prepared by the double-alloy powder mixed method was investigated. The results showed that the intrinsic coercivity of sintered Nd-Fe-B magnets increases gradually, and the squareness factor of sintered Nd-Fe-B magnets declines with increasing Dy content. The Vickers hardness of sintered Nd-Fe-B magnets increases with increasing Dy content, and the maximum fracture toughness of sintered Nd-Fe-B magnets is obtained when the Dy content is 2 wt%. The bending strength of sintered Nd-Fe-B magnets first declines, and then increases with increasing Dy content. The minimum bending strength of sintered Nd-Fe-B magnets is obtained at the Dy content of 2 wt%. The microstructure showed that the distribution of Dy content in main phase was not uniform because of the Dy diffusion of double-alloy mixed powder during the sintering process.