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

Abstract

Rare-earth permanent magnets, such as Nd2Fe14B, have been widely used in electric vehicle and wind turbine motors due to their high anisotropy field (Ha), saturation magnetization (Ms) and coercivity (Hc). 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 Ms value of ~120 emu/g and an intrinsic coercivity (Hci) value of ~85 Oe, which can be attributed to the large particle size as observed by FE-SEM.