Synthesis of Ce-Based RE₂Fe₁₄B by Solid-State Reaction and Reduction-Diffusion Process

Rare-earth permanent magnets, such as Nd₂Fe₁₄B, have been widely used in electric vehicle and wind turbine motors due to their high anisotropy field (H_a), saturation magnetization (M_s) and coercivity (H_c). Cerium (Ce) has gained attention as a potential alternative to neodymium (Nd) due to its high abundance and low cost. The relatively poor intrinsic magnetic properties of Ce magnets, however, remain a significant challenge for their industrial applications. In this study, the synthesis of Ce-based RE₂Fe₁₄B (2-14-1) phases was achieved by a modified reduction-diffusion (R-D) process using REFeO₃ (RE = Ce, Nd) as a precursor. The precursor was prepared by a solid-state reaction with CeO₂, Nd₂O₃, Fe₂O₃ and Fe powders, which is a much more suitable process for mass production and cost-effectiveness. Optimal composition and heat treatment conditions enabled the formation of single-phase Ce-based 2-14-1 particles. The as-synthesized single-phase Ce₂Fe₁₄B particles exhibited an M_s value of ~120 emu/g and an intrinsic coercivity (H_ci) value of ~85 Oe, which can be attributed to the large particle size as observed by FE-SEM.