Effects of Nb doping on the magnetic properties and microstructure of Nd26Pr3FebalCo4Ga0.42B0.92 melt-spun ribbons

The effects of Nb doping and heat treatment process on the magnetic properties, microstructure, and orientation of melt-spun ribbons with the nominal composition Nd 26 Pr 3 Fe bal Co 4 Ga 0.42 B 0.92 Nb x (x = 0–0.5) have been investigated, and the anisotropy of the powders manufactured by Nd 26 Pr 3 Fe bal Co 4 Ga 0.42 B 0.92 Nb 0.3 was discussed. Nb addition significantly reduces the grain size of the ribbons, increases the amorphous content, and increases the optimum heat-treatment temperatures for the ribbons. The highest coercivity was obtained at x = 0.3, and the optimum magnetic properties were obtained with the 690 °C annealed Nd 26 Pr 3 Fe bal Co 4 Ga 0.42 B 0.92 Nb 0.5 ribbons. After the heat-treatment processes, some Nd 2 Fe 14 B grains were deformed from equiaxed to platelet-like shapes, whose shapes were considered as needle-like in a three-dimensional perspective. The orientation of the ribbons also changed accompanying the Nb addition, showing the strong (00 l ) textures on the free-side of the Nd 26 Pr 3 Fe bal Co 4 Ga 0.42 B 0.92 Nb 0.1 and Nd 26 Pr 3 Fe bal Co 4 Ga 0.42 B 0.92 Nb 0.3 ribbons. The boned magnets, which are prepared by annealed Nd 26 Pr 3 Fe bal Co 4 Ga 0.42 B 0.92 Nb 0.3 ribbons and cured in a magnetic field, show different remanents in different directions, indicating that the ribbons are anisotropic.