Shaanxi Normal University and Collaborators Advance High-Performance Rare Earth Magnets with Less Heavy Rare Earth Usage

Highlights

• A Dy/Tb dual-layer diffusion process increased NdFeB magnet coercivity from 12.56 kOe to 22.66 kOe—an 80% improvement—while preserving magnetic strength and energy density.
• Dysprosium and terbium were found to accelerate each other's diffusion through grain boundaries, creating uniform core-shell protective regions that dramatically resist demagnetization.
• The technology could reduce heavy rare earth material intensity for EV motors, wind turbines, and defense systems without eliminating dependence on strategically sensitive Dy and Tb supplies.
• The study reinforces China's deepening competitive advantage in downstream magnet innovation, underscoring that mastering magnet science may matter as much as controlling mining output.

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A team led by Rui Chang, Guangzhu Bai, Fang Wang, and Xiaohong Xu has unveiled a potentially important breakthrough in permanent magnet technology: a new method that dramatically boosts the performance of neodymium-iron-boron (NdFeB) magnets while using heavy rare earth elements more efficiently. Published in Rare Metals (opens in a new tab), the researchers demonstrated that a carefully engineered combination of dysprosium (Dy) and terbium (Tb) can increase magnet coercivity—the ability to resist demagnetization—by more than 80% while preserving most of the magnet's strength. For industries ranging from electric vehicles and wind turbines to robotics and defense systems, the finding could help reduce heavy rare earth consumption while improving performance. The work was conducted by researchers supported through major Chinese research programs in Shaanxi Province.

Rui Chang, First Author

The investigators are affiliated with the Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, School of Materials Science and Engineering of Shaanxi Normal University; Shaanxi Key Laboratory of Advanced Magnetic Materials and Devices, Research Institute of Materials Science, Shaanxi Normal University, Taiyuan; and Institute of Advanced Magnetic Materials, Hangzhou Dianzi University, Hangzhou, China.

Why This Matters

Permanent magnets are the hidden workhorses of the modern economy. They power electric vehicle motors, offshore wind turbines, industrial automation systems, drones, and advanced military platforms. The problem is heat. As temperatures rise, magnets can lose coercivity and become easier to demagnetize. Heavy rare earth elements such as dysprosium and terbium are often added to solve this problem, but these materials are expensive, strategically important, and often difficult to source.

The Chinese researchers sought a better answer: could Dy and Tb work together more efficiently than either element alone?

How the Study Worked

The team coated commercial NdFeB magnets with ultra-thin layers of dysprosium and terbium and then heat-treated the magnets to allow the elements to diffuse through grain boundaries. They tested several Dy/Tb ratios and compared the resulting magnetic properties, microstructures, diffusion rates, and domain-wall behavior using advanced microscopy and computational modeling. The standout configuration used a 3-micron Dy layer combined with an 11-micron Tb layer.

Shaanxi Normal University

What They Found

The results were impressive. Coercivity increased from 12.56 kOe to 22.66 kOe—an 80% improvement. Even more important, the magnet retained nearly all of its original magnetic strength and energy density. The researchers found that Dy and Tb actually accelerated each other's movement through the magnet structure. This created highly uniform "core-shell" protective regions around magnetic grains, dramatically improving resistance to demagnetization. The optimized magnet approached the performance of premium commercial high-coercivity grades while maintaining excellent magnetic output.

What This Means for the Rare Earth Supply Chain

For REEx readers, the significance extends beyond materials science. Dysprosium and terbium remain among the most strategically sensitive rare earth elements, with China dominating global production and processing. Any technology that extracts more performance from every kilogram of Dy and Tb could improve supply-chain resilience, reduce material intensity, and lower costs for manufacturers. At the same time, this study reinforces China's continuing leadership in downstream magnet innovation—a reminder that competitive advantage increasingly comes not from mining alone, but from decades of accumulated expertise in processing, metallurgy, and advanced materials engineering.

Important Limitations and Open Questions

The study was conducted under laboratory conditions using relatively small magnet samples. Commercial-scale manufacturing may produce different results. Economic impacts were not evaluated, nor did the authors compare their approach against all competing diffusion technologies currently under development.

Another important question remains unresolved: even if Dy and Tb are used more efficiently, the technology still depends on the availability of those critical heavy rare earth elements. Improved utilization reduces demand intensity but does not eliminate supply-chain concentration risk.

The Bottom Line

This research demonstrates that smarter engineering—not just more material—can unlock major gains in rare earth magnet performance. While commercialization remains uncertain, the work highlights where the next competitive battleground may lie: advanced diffusion chemistry, microstructure control, and magnet manufacturing know-how. For nations seeking alternatives to Chinese rare earth dominance, the lesson is clear. Building mines is important. Mastering magnet science may be even more important.

Citation: Chang R., Bai G., Ping P., Nie Z., Liu X., Zhao L., Wang F., Xu X. Super-High Coercivity Sintered NdFeB Magnets Enabled by High-Rate Dy/Tb Grain Boundary Synergistic Diffusion. Rare Metals (2026). DOI: 10.1002/rar2.70238.

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