Wang Qiang told reporters a fact: the main problems existing in my country's NdFeB industry are the low grade and poor quality of NdFeB products. The average price of foreign products is 3-4 times that of domestic products, and the surface protection of NdFeB is improved. It is one of the keys to improve the quality and performance of NdFeB products to meet the requirements of various application environments.
"Because of the market prospects and important position of NdFeB, foreign manufacturers all regard the surface protection technology of NdFeB as an important technical secret. Therefore, to improve product competitiveness, occupy the international market, and give play to the resource advantages of rare earth countries, development must be NdFeB protection technology with my country's independent intellectual property rights." Xia Yuan said.
According to Li Guang, an associate researcher and postdoctoral fellow of the Chinese Academy of Sciences, physical vapor deposition thin film technology (PVD), such as magnetron sputtering, ion plating, and evaporation plating, is a good method for depositing thin films, and protective coatings can be obtained. Using this technology to deposit a metal film on the surface of NdFeB has high stability, coating/matrix bonding force, and high density, and has strong anti-corrosion ability in an alternating hot and cold environment. Studies have shown that if the sputtering particle energy is high enough during the deposition process, the coercivity of the magnet can be increased. In addition, the thickness of the coating during the physical vapor deposition plating process is much less affected by the corners of the magnet workpiece than electroplating and electroless plating, and there is no pollution problem in the preparation process.
"Physical vapor deposition magnetron sputtering technology applies orthogonal electric and magnetic fields between the anode (substrate) and the cathode (heavy rare earth target), so that the argon gas is excited between the electric field and the magnetic field to generate high-energy argon ions. , Argon ions are deposited on the surface of the substrate in atomic form by hitting the heavy rare earth target, so that the excited high energy heavy rare earth target atoms are uniformly and firmly attached to the surface of the substrate, which is beneficial to the subsequent thermal diffusion of high vacuum heavy rare earth atoms Process." Zhang Yanjie said, currently 15 patents have been applied for, including one authorized invention patent, 6 utility model patents, and 4 trademarks applied for and authorized.
The use of green and pollution-free physical vapor deposition technology is the development direction of NdFeB protection in the future. my country's first continuous green and pollution-free physical vapor deposition industrialization demonstration production line with an annual output of 100 tons has been built. The products can not only meet the requirements of emerging applications such as wind power and electric vehicles, but also adopt high-temperature samarium cobalt permanent magnets protected by physical vapor deposition It can also meet the needs of high-tech fields. It is of great significance to promote the industrialization of green coatings and realize the improvement of the quality of rare earth permanent magnetic materials in my country.
