Since their discovery thousands of years ago, magnets have fascinated humankind with their unique properties. Even today, scientists are studying and finding new applications for these materials.
In 1984, the development of neodymium-iron-boron (Nd-Fe-B) magnets revolutionized this field. Known for their unparalleled magnetic strength, these magnets have now become ubiquitous, serving as critical components in renewable energy systems and advanced electronics. However, their susceptibility to degradation under moisture, salt spray, and temperature fluctuations has, thus far, strongly limited their deployment in harsh environments. Traditional protective coatings such as Ni-Cu-Ni, Zn, and epoxy resin often fail under prolonged exposure, leading to catastrophic magnet failure.
To overcome these challenges, a team of researchers from the Institute of Advanced Magnetic Materials at Hangzhou Dianzi University, led by Dr. Zhen Shi (first author) and Prof. Xuefeng Zhang (corresponding author), has developed a "slippery liquid-infused porous surface" (SLIPS) coating for Nd-Fe-B magnets through a multi-dimensional design strategy. Their recent work has been published in the journal Small on 14 April 2025.
Elaborating on their findings, Prof. Zhang says, "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."
In this study, the team chemically engineered silica nanoparticles to form a dense polymer network with enhanced interfacial adhesion and locked lubricant film. Consequently, the resultant coating enables Nd-Fe-B magnets to resist corrosion, humidity, mechanical stress, and extreme temperatures with unprecedented durability.
Through extensive experimentation, the researchers found that there was no corrosion detected even after 136-day immersion in 3.5 wt.% saltwater. Furthermore, the novel SLIPS coating delays ice formation with 10-fold longer freezing time and reduces ice adhesion strength by 75% at -20°C, as well as repairs mechanical scratches autonomously and restores surface functionality.
Compared to commercial Ni-Cu-Ni, Zn, and epoxy resin coatings, SLIPS coating demonstrates super stable corrosion protection for Nd-Fe-B magnets. In electrochemical experiments, the impedance modulus of SLIPS coating at 0.1 Hz can be maintained at 3.31×10⁸ Ω·cm² even after 132-day immersion, far surpassing that of commercial coatings. Notably, the impedance modulus of all commercial coatings deteriorated within 14 days.
Dr. Shi briefly highlights the technological impact of this new coating. "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."
Lastly, the research team further noted that the self-healing capability of the SLIPS coating ensures longevity even after physical damage, a critical feature for mission-critical systems in remote or inaccessible locations.
While initially tested for offshore wind turbines, the robustness of the proposed technology suggests transformative potential across various industries. Aerospace engineers could leverage these magnets for lightweight, high-efficiency motors in satellites, while polar research equipment and deep-sea exploration tools utilizing this innovation could achieve unprecedented reliability.
Reference
Authors: Zhen Shi1, Chenxi Fang1, Jiaqian Li2, Sateesh Bandaru1, Muwen Liu2, Lizhong Zhao1, and Xuefeng Zhang1
DOI: https://doi.org/10.1002/smll.202500629
Affiliations:
1Institute of Advanced Magnetic Materials, College of Materials and Environmental Engineering, Hangzhou Dianzi University, People's Republic of China
2School of Energy and Power Engineering, Shandong University, People's Republic of China.
About Dr. Zhen Shi from Hangzhou Dianzi University
Dr. Zhen Shi is a researcher at the Institute of Advanced Magnetic Materials, Hangzhou Dianzi University, specializing in surface protection of high-performance magnets like Nd-Fe-B for harsh environments. His groundbreaking work includes the development of superhydrophobic and SLIPS magnet, offering exceptional resistance to corrosion, humidity, and extreme temperatures. Dr. Shi's research bridges laboratory innovation with real-world applications, aiming to improve the reliability and longevity of magnetic components in industries such as aerospace and renewable energy.
About Professor Xuefeng Zhang from Hangzhou Dianzi University
Prof. Xuefeng Zhang is the academic leader of the Institute of Advanced Magnetic Materials, Hangzhou Dianzi University. He is a distinguished young scholar of the National Science Fund and has published over 100 SCI-indexed papers in prestigious journals such as Physics Review Letters, Nature Communications, Angewandte Chemie International Edition, etc. Meanwhile, he is devoted to establishing close collaborations with industries to advance the engineering applications of magnetic materials and technologies.
Funding Information
This research was funded by National Science Fund for Distinguished Young Scholars (Grant Number: 52225312); National Natural Science Foundation of China (Grant Number: 52371184); Fundamental Research Funds for the Provincial Universities of Zhejiang (Grant Number: GK249909299001-005); China Postdoctoral Science Foundation (Grant Number: 2023M743618); and Natural Science Foundation of Zhejiang Province (Grant Number: LY22E010002).
