Reviewed by Lexie CornerMay 13 2025
A research team from the Institute of Advanced Magnetic Materials at Hangzhou Dianzi University has developed a “slippery liquid-infused porous surface” (SLIPS) coating for neodymium-iron-boron (Nd-Fe-B) magnets using a multi-layered design strategy. Their findings were recently published in Small.
Magnets have fascinated researchers for centuries, and their properties continue to drive innovation in modern technology.
A major leap in magnet technology came in 1984 with the invention of Nd-Fe-B magnets, known for their exceptional magnetic strength. These rare-earth magnets are now widely used in renewable energy systems, electric motors, and advanced electronics.
Nd-Fe-B magnets are prone to degradation when exposed to moisture, salt spray, and temperature changes. Standard coatings like Ni-Cu-Ni, zinc, and epoxy often deteriorate over time, leading to corrosion and reduced magnetic performance.
To address this, the team, led by Dr. Zhen Shi (first author) and Professor Xuefeng Zhang (corresponding author), developed a SLIPS coating that improves resistance to environmental damage.
This technology could revolutionize motor applications, ranging from aerospace systems to deep-sea robotics and polar infrastructure, by preventing saltwater, humidity, and temperature fluctuation-induced magnet degradation. Moreover, we can significantly extend motor lifespans while reducing the maintenance costs.
Xuefeng Zhang, Professor, Corresponding Author, Institute of Advanced Magnetic Materials, Hangzhou Dianzi University
The team chemically modified silica nanoparticles to form a strong polymer network, improving layer adhesion and securing a stable lubricant layer. This structure gave the SLIPS coating high resistance to corrosion, humidity, mechanical wear, and extreme temperatures.
Tests showed no corrosion after 136 days of immersion in a 3.5 wt.% saltwater solution.
The coating also delayed ice formation by a factor of ten and reduced ice adhesion strength by 75 % at -20 °C. It was able to self-heal surface scratches and recover functionality.
Compared to commercial Ni-Cu-Ni, zinc, and epoxy coatings, the SLIPS coating offered longer-lasting protection. Electrochemical testing showed that its impedance modulus at 0.1 Hz remained at 3.31 × 10⁸ Ω·cm² after 132 days, while other coatings degraded within 14 days.
Dr. Zhen Shi noted the potential of this coating to improve magnet durability in harsh environments.
Our multidimensional design bridges the gap between laboratory innovation and real-world applications. By addressing corrosion and icing simultaneously, we have transformed Nd-Fe-B magnets into reliable components even for the most demanding environments.
Dr. Zhen Shi, Study First Author, Institute of Advanced Magnetic Materials, Hangzhou Dianzi University
The researchers emphasized that the self-healing property of the SLIPS coating supports long-term performance even after physical damage. This feature is especially important for critical systems located in remote or difficult-to-access environments.
While the coating was initially evaluated for offshore wind turbine applications, its durability suggests broader potential. For example, it could support the development of lightweight, high-efficiency motors in aerospace, or improve the reliability of equipment used in polar research and deep-sea exploration.
The study was supported by the National Science Fund for Distinguished Young Scholars (Grant No. 52225312), the National Natural Science Foundation of China (Grant No. 52371184), the Fundamental Research Funds for the Provincial Universities of Zhejiang (Grant No. GK249909299001-005), the China Postdoctoral Science Foundation (Grant No. 2023M743618), and the Natural Science Foundation of Zhejiang Province (Grant No. LY22E010002).
Journal Reference:
Shi, Z., et al. (2025). Multi-Dimensional Design of Slippery Liquid-Infused Coatings Empowering Long-Term Corrosion Protection for Sintered Nd-Fe-B Magnets in Harsh Environments. Small. doi.org/10.1002/smll.202500629