On January 19, 2024, a company in Yantai applied for a patent titled “A kind of sintered neodymium-iron-boron magnet with high coercivity consistency and its preparation method”, Publication No. CN117410054A, with a filing date of October 2023, according to a notice from the China Intellectual Property Office.
According to the patent abstract, the present invention realizes a better combination of the heavy rare earth diffusion layer and the magnet substrate surface by regulating the temperature and humidity at the diffusion stage at the grain boundary, as well as the water content of the diffusion layer. At the same time, the use of metal plates in the vacuum diffusion furnace, the use of metal plates of high thermal conductivity and high thermal conductivity, so that the diffusion furnace cavity temperature change rate is more uniform, and effectively improve the center of the furnace cavity of the warming position, shorten the apex of the furnace and the body of the material temperature of the center of the body to reach the temperature of the diffusion of the time △ T, and then improve the consistency of the whole furnace products, the same magnet performance.
This research makes the sintered NdFeB magnets more widely used.