Bulk Fabrication and Coercivity Enhancement of Ce-Based RE₂Fe₁₄B Prepared by a Modified Reduction-Diffusion Process.

Area of Science:

• Materials Science
• Solid State Chemistry
• Magnetism

Background:

• Rare-earth (RE) permanent magnets, especially Nd2Fe14B, are critical for high-performance technologies.
• Supply chain risks and high costs of critical RE elements like Neodymium (Nd) necessitate alternatives.
• Previous modified reduction-diffusion (R-D) processes faced challenges with phase decomposition during sintering.

Purpose of the Study:

• To develop cost-effective, high-performance Ce-based RE2Fe14B (2-14-1) permanent magnets.
• To overcome phase decomposition issues in bulk magnet fabrication using the modified R-D process.
• To enhance magnetic properties by refining particle size and engineering grain boundaries.

Main Methods:

• Synthesized 2-14-1 compounds via a modified R-D process.
• Applied high-energy ball-milling for particle size refinement.
• Utilized heat-treatment with Calcium (Ca) and addition of a Nd70Al20Cu10 alloy for grain boundary engineering.

Main Results:

• Suppressed phase decomposition and promoted phase recovery using Ca heat-treatment.
• Achieved enhanced magnetic decoupling through uniform grain boundary formation with the Nd-Al-Cu alloy.
• Significantly increased coercivity up to 10 kOe for Ce-based 2-14-1 magnets.

Conclusions:

• A dual strategy of particle size refinement and grain boundary engineering effectively enhances magnetic properties of Ce-based 2-14-1 magnets.
• The developed method offers a viable pathway for producing cost-effective and high-performance rare-earth permanent magnets.
• This research contributes to advancing efficient rare-earth magnet technology by reducing reliance on critical elements.