Enhanced comprehensive magnetic performance sintered Nd-Fe-B magnet via a novel vibration-assisted pulsed magnetic field orientation process

Abstract

Achieving high coercivity and remanence simultaneously remains a primary challenge in the development of high comprehensive magnetic performance sintered Nd-Fe-B magnets. In this paper, a novel molding process is proposed, integrating a pulsed magnetic field (maximum orientation field: 4.5 T) with high-frequency vibration during the orientation stage while eliminating the application of pressure. This innovative approach effectively preserves particle orientation integrity, leading to enhanced magnetic properties. The optimal magnetic properties with a remanence of 15.19 kGs were obtained, surpassing that (14.99 kGs) of traditional molding process magnet. X-ray diffraction (XRD) analysis confirmed a significantly improved orientation degree, with the intensity ratio I₍₀₀₆₎/I₍₁₀₅₎ increasing from 1.36 (traditional process) to 2.19 (novel process). Discrete element method (DEM) simulations revealed that the combined effects of the high-intensity pulsed magnetic field, vibration-induced uniform particle distribution, and novel molding contribute to the improved orientation. Moreover, based on this high-remanence substrate magnet, a grain boundary diffusion (GBD) magnet with a remanence of 15 kGs and a coercivity of 17.42 kOe was successfully developed. This work provides a novel strategy for future development of high comprehensive performance sintered Nd-Fe-B magnets.