High performance corrosion resistant magnetized diversity bonded magnets How to achieve a balance between high magnetism and corrosion resistance?
Publish Time: 2025-03-24
As an important permanent magnetic material, bonded NdFeB magnets have been widely used in new energy vehicles, consumer electronics, medical equipment and other fields due to their high magnetic properties, excellent machinability and diversified shape design capabilities. However, the inherent susceptibility to corrosion of NdFeB materials limits their application in harsh environments. In order to achieve a balance between high magnetism and corrosion resistance, researchers and engineers have conducted in-depth explorations from multiple aspects such as material design, surface treatment and preparation process.First of all, material design is the basis for achieving a balance between high magnetism and corrosion resistance. The high magnetism of NdFeB magnets mainly comes from their unique crystal structure and the addition of rare earth elements. However, rare earth elements (such as neodymium, dysprosium, etc.) have high chemical activity and are easily reacted with oxygen, moisture and corrosive media in the environment, resulting in oxidation and even pulverization of the material surface. In order to solve this problem, researchers optimized the microstructure and improved the intrinsic corrosion resistance of the material by adding appropriate amounts of cobalt, aluminum, copper and other elements to NdFeB alloys. For example, the addition of cobalt can significantly improve the thermal stability and oxidation resistance of NdFeB magnets, while aluminum and copper help to form a dense oxide layer and slow down the corrosion process.Secondly, surface treatment technology is a key means to improve the corrosion resistance of bonded NdFeB magnets. Common surface treatment methods include electroplating, chemical plating, spraying and physical vapor deposition. Among them, electroplating is one of the most commonly used technologies. By plating a layer of nickel, zinc or nickel-copper-nickel and other multi-layer metal plating on the surface of the magnet, the contact between the NdFeB material and the external environment can be effectively isolated to prevent corrosion. In addition, chemical plating of nickel-phosphorus alloy is also an effective surface treatment method. Its coating is uniform and dense, and has excellent corrosion resistance and wear resistance. In recent years, with the improvement of environmental protection requirements, green surface treatment technologies such as chromium-free passivation and organic coating have gradually been applied, further improving the environmental performance and corrosion resistance of bonded NdFeB magnets.In addition to material design and surface treatment, the optimization of preparation process also plays an important role in achieving a balance between high magnetism and corrosion resistance. The preparation process of bonded NdFeB magnets includes multiple links such as magnetic powder preparation, mixing, molding, curing and post-processing. In the magnetic powder preparation stage, by optimizing the processes such as smelting, rapid quenching and hydrogen crushing, high-purity and low-oxygen content NdFeB magnetic powder can be obtained, thereby improving the intrinsic corrosion resistance of the material. In the molding and curing stages, the use of advanced injection molding or compression molding technology can ensure the uniformity and density of the internal structure of the magnet, reduce porosity and defects, and reduce the risk of corrosion medium penetration.In addition, the selection and optimization of the binder is also an important link in improving the performance of bonded NdFeB magnets. Although traditional epoxy resin binders have good bonding strength and mechanical properties, their heat resistance and corrosion resistance are poor. In recent years, researchers have developed a variety of new binders, such as high-performance polymers such as polyamide and polyetheretherketone. These materials not only have excellent corrosion resistance, but also maintain stable performance in high temperature environments, further broadening the application range of bonded NdFeB magnets.In practical applications, high performance corrosion resistant magnetized diversity bonded magnets also need to comprehensively consider the specific requirements of the use environment. For example, in a high temperature and high humidity environment, the magnet needs to have higher thermal stability and antioxidant capacity; while in a corrosive medium of strong acid and alkali, a more chemically resistant surface treatment solution needs to be selected. Through targeted material design and process optimization, the performance advantages of bonded NdFeB magnets can be maximized to meet the needs of different application scenarios.In general, the realization of high performance corrosion resistant magnetized diversity bonded magnets is a systematic project, which requires comprehensive optimization from multiple aspects such as material design, surface treatment, preparation process and use environment. With the continuous emergence of new materials, new processes and new technologies, the performance of bonded NdFeB magnets will be further improved, providing more reliable support for the development of modern industry. In the future, with the improvement of environmental protection and sustainable development requirements, the application of green preparation technology and renewable materials will also become an important direction for the development of bonded NdFeB magnets.
