In the relentless quest to enhance the durability and performance of neodymium-iron-boron (Nd-Fe-B) magnets, a transformative coating technology has emerged, redefining protective strategies for these powerful magnetic materials. Developed by a team of researchers at Hangzhou Dianzi University, this novel slippery liquid-infused porous surface (SLIPS) coating promises to significantly extend the lifespan and reliability of Nd-Fe-B magnets in extreme environments. The implications of this breakthrough stretch across renewable energy, aerospace, deep-sea exploration, and polar infrastructures, where the resilience of magnetic components often dictates the success or failure of entire systems.
Nd-Fe-B magnets, first introduced in the mid-1980s, have since become indispensable in modern technology due to their exceptional magnetic strength relative to size and weight. They form the backbone of high-efficiency electric motors, generators for renewable energy, and compact electronics. However, these magnets’ application has been hampered by their vulnerability to degradation caused by environmental stressors such as moisture intrusion, salt spray, temperature fluctuations, and mechanical abrasion. Standard protective coatings like nickel-copper-nickel, zinc, and epoxy resin have largely fallen short under prolonged exposure to such harsh conditions, leading to magnet corrosion, surface deterioration, and eventual failure.
Addressing these longstanding challenges required a multifaceted approach, which the research team led by Dr. Zhen Shi and Prof. Xuefeng Zhang strategically embraced. At the heart of their innovation lies the SLIPS coating, engineered through a sophisticated multidimensional design that merges surface chemistry, nanostructured interfaces, and lubricant-infused porous networks. This composite architecture not only forms a formidable physical barrier preventing corrosive agents from reaching the magnet’s surface but also imparts self-healing capabilities and anti-icing functionalities, which are critical for operation in polar and offshore environments.
The research underscores the core mechanism of corrosion resistance stemming from chemically modified silica nanoparticles integrated into a polymer matrix. This network exhibits enhanced interfacial adhesion, effectively anchoring a lubricant film within the porous coating. The lubricant layer acts as a dynamic shield, repelling water and salt ions, thus inhibiting corrosive processes. Importantly, the coating’s interlocked structure ensures that even under mechanical stress, including scratches and impacts, the lubricant can redistribute itself, autonomously repairing damage and maintaining continuous protection.
Extensive environmental testing solidifies the efficacy of the SLIPS coating. When subjected to immersion in a 3.5 weight percent saltwater solution—a scenario mimicking aggressive marine conditions—for over 136 days, the coated magnets exhibited zero signs of corrosion. This resilience far outperformed commercial coatings, which typically deteriorated within two weeks under similar tests. Electrochemical impedance spectroscopy revealed an extraordinary impedance modulus of 3.31×10⁸ Ω·cm² at 0.1 Hz after 132 days, a figure several orders of magnitude higher than commercial counterparts, indicating a near-impermeable barrier to corrosive electrolytes.
Beyond corrosion, the coating significantly improves anti-icing performance, a critical factor for magnets deployed in cold climates or high-altitude applications. The researchers demonstrated that the SLIPS surface delays ice nucleation and growth, extending the freezing onset time by a factor of ten compared to uncoated magnets. Moreover, it reduces ice adhesion strength by 75% at subzero temperatures (-20°C), which can minimize mechanical damage during ice shedding and reduce energy consumption associated with de-icing procedures in industrial setups.
The coating’s self-healing property is notable. Unlike rigid protective layers prone to cracking and degradation over time, the lubricated porous surface can autonomously reconstruct after sustaining mechanical abrasions. This dynamic recovery maintains magnet functionality without interruption, ensuring operational continuity in mission-critical systems situated in remote or inaccessible locations where maintenance opportunities are scarce or non-existent.
The technological implications of this advancement are profound. As Prof. Zhang articulates, integrating SLIPS coatings into Nd-Fe-B magnets could revolutionize motors operating in challenging environments—from aerospace propulsion systems, where weight and durability are paramount, to offshore wind turbines subjected to relentless salt spray and fluctuating oceanic conditions. The extended lifespan and reduced maintenance burden translate into economic and environmental benefits, enhancing the viability and sustainability of green energy technologies.
From a materials science perspective, this innovation represents a significant leap forward by bridging the gap between laboratory breakthroughs and industrial applicability. The design strategy, which synchronizes nanoscale chemical engineering with macroscopic durability demands, exemplifies an emerging paradigm in materials protection—where multifunctionality, such as combined corrosion resistance, anti-icing, and self-healing, becomes a baseline expectation rather than a supplementary feature.
The research team’s experimental methodology featured rigorous electrochemical corrosion assays, long-duration immersion studies, mechanical abrasion tests, and low-temperature icing evaluations. This comprehensive approach ensured a holistic understanding of the coating’s performance, durability, and potential failure modes, setting a new standard for magnet protection protocols. Their publication in the renowned journal Small consolidates the scientific foundation underpinning this technology and paves the way for subsequent applied research and commercialization.
In addition to academic impact, the invention holds tangible value for an array of industries. Aerospace engineering could leverage these coatings to produce lighter, more reliable motors in aircraft and satellites, where exposure to temperature extremes and moisture varies drastically and unpredictably. Deep-sea exploration tools—regularly battered by corrosive saltwater at great depths—stand to benefit from enhanced operational lifespans, improving safety and mission effectiveness. Polar research stations and instrumentation, often isolated and exposed to extreme cold and ice formation, represent another critical application domain.
The SLIPS coating innovation is backed by substantial funding from prestigious scientific foundations in China, evidencing the strategic importance placed on advancing magnetic materials. The interdisciplinary collaboration between institutes focusing on magnetic materials and energy engineering highlights the integrated approach needed to tackle complex material performance challenges. Such support also underscores the global relevance and anticipated transformative impact of this technology.
Dr. Zhen Shi and Prof. Xuefeng Zhang exemplify the convergence of deep scientific expertise and applied engineering foresight. Their combined efforts not only solve a pressing materials durability issue but also foster a new generation of magnet coatings tailored for the demands of future technologies. With over 100 SCI-indexed publications, Prof. Zhang’s leadership and industrial collaboration initiatives ensure that this SLIPS technology will transition swiftly from research environments into practical, scalable applications shaping the future of magnetic component design.
Ultimately, this multidimensional SLIPS coating heralds a new era where Nd-Fe-B magnets transcend traditional environmental limitations. It holds the promise of catalyzing advancements in clean energy, high-performance computing, robotics, and beyond. As society increasingly demands reliable, lightweight, and long-lasting materials, innovations like this stand at the nexus of scientific progression and technological revolution.
Subject of Research: Not applicable
Article Title: Multi-dimensional Design of Slippery Liquid-infused Coatings Empowering Long-term Corrosion Protection for Sintered Nd-Fe-B Magnets in Harsh Environments
News Publication Date: 14-Apr-2025
Web References: http://dx.doi.org/10.1002/smll.202500629
References:
Shi, Zhen; Fang, Chenxi; Li, Jiaqian; Bandaru, Sateesh; Liu, Muwen; Zhao, Lizhong; Zhang, Xuefeng. "Multi-dimensional Design of Slippery Liquid-infused Coatings Empowering Long-term Corrosion Protection for Sintered Nd-Fe-B Magnets in Harsh Environments." Small. 14 April 2025. DOI: 10.1002/smll.202500629
Image Credits: Shi et al. from Hangzhou Dianzi University, Hangzhou, China.
Keywords
Chemistry, Materials science, Physical sciences, Applied sciences and engineering, Material properties, Physics
