Thermal Synthesis and Structural Optimization of Fe <sub>3</sub> BO <sub>6</sub> Nanoparticles for Improved Magnetic Performance in Nd–Fe–B Alloys
Abstract
ABSTRACT This work describes the thermal synthesis and structural optimization of Fe3BO 6 nanoparticles (NPs) as boron‐containing precursors for nanostructured Nd–Fe–B permanent magnets. Amorphous Fe 3 BO 6 NPs were obtained by chemical precipitation from FeCl 3 /NaBH 4 solutions and crystallized by controlled heat treatment. Phase evolution was monitored by TG–DSC, XRD, and FTIR, while SEM, TEM, and DLS characterized morphology and size distribution. Annealing at 530°C yields Fe 3 BO 6 ·3 α ‐Fe 2 O 3 NPs with a narrow size distribution (50 ± 10 nm) and reduced aggregation, suitable for chemically assisted nanostructuring. These optimized NPs, combined with Nd 2 O 3 and Fe 2 O 3 , were used in a reduction–diffusion route to prepare Nd–Fe–B alloys with different nominal compositions. The best composition, Nd 16 Fe 76 B 8 , forms single‐phase Nd 2 Fe 14 B and exhibits high coercivity (Hc = 8439 Oe) with stable remanence, surpassing several reported chemically synthesized Nd–Fe–B systems. The use of simple inorganic precursors, moderate temperatures, and controlled nanoscale structure makes this Fe 3 BO 6 ‐based route attractive for scalable, resource‐efficient production of powders for advanced bonded magnets and other high‐performance applications.