R-T-B sintered magnet and preparation method thereof

US11705257B2 · kind B2 · utility

Assignees

• GRIREM ADVANCED MATERIALS CO., LTD. · CN
• Rare Earth Functional Materials (Xiong'an) Innovation Center Co., Ltd. · CN
• Griceon (Rongcheng) Co., Ltd. · CN

Inventors

• Yang Luo · Amherst, US
• Dunbo Yu · Beijing, CN
• Wei Zhu · Shandong, CN
• Xinyuan BAI · Beijing, CN
• Xiao LIN · Suzhou, CN
• Shengjie ZHU · Beijing, CN
• Zilong Wang · Zhejiang, CN
• Haijun Peng · Suzhou, CN

Key dates

• Filing date: Apr 29, 2021
• Grant date: Jul 18, 2023
• Expiry date: Jul 8, 2041

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01F41/0293
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The present invention relates to an R-T-B sintered magnet and a preparation method thereof. The sintered magnet includes a grain boundary region T1, a shell layer region T2 and an R2Fe14B grain region T3; at 10 μm to 60 μm from a surface of the sintered magnet toward a center thereof, an area ratio of the shell layer region T2 to the R2Fe14B grain region T3 is 0.1 to 0.3, and a thickness of the shell layer region T2 is 0.5 μm to 1.2 μm; and an average coating percent of the shell layer region T2 on the R2Fe14B grain region T3 is 80% or more. In the present invention, by optimizing a preparation process and a microstructure of a traditional rare earth permanent magnet, diffusion efficiency of heavy rare earth in the magnet is improved, such that coercivity of the magnet is greatly improved, and manufacturing cost is reduced.