Using Nanocrystalline HDDR Powders in the Additive Manufacturing of Bonded Nd-Fe-B Magnets

This study explored the application of high coercivity nanocrystalline powders in the additive manufacturing (AM) of bonded Nd-Fe-B magnets using two techniques: laser powder bed fusion (LPBF) and stereolithography (SLA). The nanocrystalline powders were obtained through hydrogen decrepitation (HD) and hydrogenation disproportionation desorption recombination (HDDR) of Nd-Fe-B alloys. These high-quality powders were mixed with a binder and processed via LPBF and SLA to obtain bonded magnets. LPBF is a popular technique due to its design flexibility and reduced material waste. On the other hand, SLA also shows promise in producing bonded magnets, although there is limited literature on this topic. The impact of HDDR and AM processing parameters on the magnetic properties and microstructure of the powders and magnets was investigated. We were able to successfully produce isotropic HDDR powder with coercivity values up to 850 kA/m, and also bonded magnets via LPBF and SLA with various binder fractions, while maintaining the high coercivity of the HDDR particles. Exploring different AM techniques paves the way for the development of smart magnetic materials.