New Study Suggests Smarter Use of Scarce Dysprosium Could Produce Stronger Magnets with Less Heavy Rare Earth Material

Highlights

• Applying small amounts of dysprosium to magnet surfaces via grain boundary diffusion outperforms conventional methods that distribute the element throughout the entire magnet.
• Magnets with little or no initial dysprosium content gained the greatest performance boost from diffusion treatment, revealing diminishing returns at higher Dy concentrations.
• The technique concentrates dysprosium around microscopic grain boundaries, forming a Dy-rich shell that resists demagnetization at high operating temperatures.
• More efficient dysprosium use could lower production costs and reduce dependence on China-dominated heavy rare earth supply chains for EV motors and defense applications.
• The study is laboratory-scale and requires significant engineering and commercial validation before industrial adoption is feasible.

A new study (opens in a new tab) led by Weiyuan Zhang (opens in a new tab), School of Automotive Materials, Hubei University of Automotive Technology, Shiya (opens in a new tab), China, and colleagues, published in Vacuum, demonstrates that manufacturers may be able to use the scarce heavy rare earth element dysprosium (Dy) much more efficiently when producing high-performance neodymium-iron-boron (Nd-Fe-B) permanent magnets. Working with collaborators from Chinese research institutions, the team found that applying relatively small amounts of dysprosium to finished magnets through a process known as grain boundary diffusion improved resistance to demagnetization more effectively than distributing the same amount throughout the entire magnet during manufacturing. If the approach proves commercially scalable, it could reduce heavy rare earth consumption, improve magnet performance, and help lower production costs for applications ranging from electric vehicles to industrial motors—although important manufacturing and supply-chain questions remain.

Hubei University of Automotive Technology, School of Automotive Materials

Study Methods

The researchers manufactured several Nd-Fe-B magnets containing different initial concentrations of dysprosium. After sintering, they applied thin coatings of additional dysprosium to the magnet surfaces and heat-treated the samples so the element diffused inward along microscopic grain boundaries. They then compared the resulting magnetic properties with those of magnets produced using the conventional dual-alloy powder mixing method.

Key Findings

The central finding is surprisingly intuitive: placing dysprosium where it is needed matters more than simply using more of it.

Magnets containing little or no dysprosium initially experienced the greatest improvement after grain boundary diffusion. Rather than dispersing expensive dysprosium throughout the entire magnet, the diffusion process concentrated it around the microscopic boundaries of magnetic grains, creating a thin Dy-rich shell that significantly increased the magnet's resistance to losing its magnetic strength at elevated temperatures. The researchers also found that magnets already containing higher dysprosium concentrations benefited less from additional diffusion treatment, suggesting diminishing returns as Dy content increases.

Why This Matters

Dysprosium is one of the world's most strategically important heavy rare earth elements. It enables permanent magnets to maintain their magnetic strength under the high operating temperatures encountered in electric vehicle motors, robotics, aerospace systems, defense technologies, and many industrial applications. Because global production of heavy rare earths remains heavily concentrated within China's sphere of influence, every improvement in dysprosium efficiency has potential strategic significance. If manufacturers can achieve equivalent or better magnetic performance while using less dysprosium, they could reduce both production costs and dependence on one of the most supply-constrained critical minerals.

Study Limitations

The research remains a laboratory-scale materials science investigation. It does not evaluate commercial manufacturing economics, large-scale production yields, long-term durability, quality control, or industrial scalability. Nor does it address the broader geopolitical reality that global heavy rare earth supplies remain highly concentrated. While the results are scientifically promising, considerable engineering and commercial validation will be required before widespread industrial adoption.

Looking Ahead

This study reinforces an increasingly important principle in permanent magnet technology: future competitiveness may depend less on consuming larger quantities of critical minerals and more on deploying them more intelligently. As manufacturers worldwide seek to reduce exposure to constrained heavy rare earth supply chains, innovations such as grain boundary diffusion could become an important part of the next generation of high-performance magnet manufacturing. Whether these laboratory advances translate into economically viable industrial production will be the question the industry watches most closely.

Citation: Zhang, W., Wang, L., Yang, F., Ma, Y., Hu, Z., Zeng, C., & Wang, T. The role of Dy in multi-main-phase Nd-Dy-Fe-B magnets by Dy grain boundary diffusion. Vacuum, Volume 251 (2026), Article 115367. https://doi.org/10.1016/j.vacuum.2026.115367 (opens in a new tab)