Performance Enhancement of LCM-Based Additively Manufactured Magnetic Composites via Spark Plasma Sintering

Abstract

This study explores spark plasma sintering (SPS) to improve the microstructural integrity and magnetic performance of NdFeB composite parts produced by lithography-based composites manufacturing (LCM). The composites, containing 84 wt.% NdFeB in a photosensitive polymer matrix, were magnetically aligned during printing using an in-situ field. SPS, applying pulsed current and uniaxial pressure under vacuum, was used to achieve densification while limiting grain growth. Samples were sintered at various temperatures with or without a magnetic field. Microstructure was examined via electron backscatter diffraction (EBSD) and X-ray diffraction (XRD), and magnetic properties were measured by Vibrating Sample Magnetometer (VSM). Optimized moderate-temperature, field-assisted sintering enhanced densification and magnetic anisotropy, whereas excessive sintering caused degradation. The combined use of in-situ magnetic alignment and SPS enables dense, anisotropic additively manufactured NdFeB composites with improved performance.