Nanotechnology Empowers New Progress in Microstructure Optimization of NdFeB Magnets

Recently, the "Nanoscale Grain Boundary Regulation" technology jointly developed by Ningbo Yunsheng and the School of Materials Science and Engineering at Zhejiang University has passed the appraisal by China's Ministry of Industry and Information Technology. Leveraging atomic layer deposition nano-coating technology, this innovation enables precise control over the microstructure of NdFeB magnets, resulting in a 23% increase in coercivity and providing core support for the mass production of highly stable magnets.

Traditional NdFeB magnets exhibit uneven grain size distribution (ranging from 5 to 20 micrometers), with magnetic domain leakage prone to occur at grain boundaries. The new technology employs a 5-nanometer-scale rare-earth oxide coating, forming a continuous covering layer on grain surfaces through magnetron sputtering, which controls grain size deviation within ±0.8 micrometers. High-resolution electron microscopy reveals that the uniformity of grain boundary phase thickness has improved to 92%, a 40 percentage point increase compared to traditional processes, effectively blocking the expansion of reverse magnetic domains.

The research team has innovatively designed a composite system combining "nanoscale doping + magnetic field sintering," reducing the porosity inside the magnets to below 0.3% and achieving a temperature resistance exceeding 200℃. Third-party testing shows that the magnetic performance decay rate at 150℃ has decreased from 8% to 3.2%, extending the service life to 12,000 hours. Currently, this technology has been implemented on a 2,000-ton production line, with products passing extreme environment tests conducted by companies such as CATL and DJI.

"This marks China's entry into the international ranks in the field of magnet microstructure regulation," noted an expert from the China Electronics Materials Industry Association. The technology enables a 15% reduction in the amount of magnets used in drive motors for new energy vehicles, translating to a savings of 680 tons of rare-earth resources annually based on an annual demand of 80,000 tons. Relevant findings have been published in Nano Letters, with 12 authorized invention patents secured. Large-scale application is anticipated by 2025.