Enhancing the coercivity of Nd-Cu-diffused Nd-Fe-B permanent magnets by Nb-assisted grain boundary pinning

oleh: M. B. Siva Kumar, D. Prabhu, M. Sadhasivam, B. Manjusha, N. Chandrasekaran, K. G. Pradeep, G. Sundararajan, R. Gopalan

Format: Article
Diterbitkan: Taylor & Francis Group 2022-12-01

Deskripsi

We report the effect of grain boundary diffusion of the Nd-Cu eutectic phase and the influence of Nb on the microstructure and magnetic properties of Nd-Fe-B melt-spun ribbons. The Atom probe tomography analysis indicated the presence of Nb clusters (∼10 nm), which possibly restricts grain growth during diffusion annealing while facilitating Nd-Cu grain boundary decoration. Correspondingly, the coercivity was enhanced from the initial 1.2 T of the as-prepared to 2.1 T for the 20 wt.% Nd-Cu diffusion annealed (600°C, 2 h). Incidentally, the as-diffused sample exhibited a high coercivity of ∼1 T at 150°C, making it suitable for high-temperature applications.