Production of anisotropic hot deformed Nd-Fe-B magnets with the addition of Pr-Cu-Al alloy based on nanocomposite ribbon

•A short-range grain boundary diffusion process is proposed to improve the uniformity of coercivity.•The disappearance of α-Fe phase and the formation of intergranular phases contribute to huge improvement of coercivity.•Anisotropic hot deformed Nd-Fe-B magnets with high performance were fabricated.•The metallurgical behavior of elements and intergranular phase evolution are investigated. [Display omitted] For usual grain boundary diffusion, the diffused source infiltrates into the magnet from the surface, and a long diffusion distance leads to non-uniform distribution of elements, which seriously restricts the improvement of properties and reduces the uniformity of coercivity. In this work, based on nanocomposite Nd-Fe-B ribbon, a short-range grain boundary diffusion (SRGBD) process is employed to improve coercivity, obtaining a high coercivity of 24.27 kOe in PrCuAl-diffused nanocomposite powder, increasing by 233.0% comparing to the initial ribbon. By spark plasma sintering (SPS) technique, an isotropic magnet with high coercivity of 24.13 kOe is prepared, and meanwhile, good uniformity of coercivity is also achieved. The disappearance of the α-Fe phase and the formation of intergranular phases contribute to a huge improvement of coercivity. At last, with the help of the intergranular phase, established by SRGBD, anisotropic magnets are successfully prepared through hot deformation, which the optimum magnetic properties with Hci = 18.99 kOe, Jr = 1.08 T, and (BH)max = 215 kJ/m3 can be achieved.