Rare-earth intermetallic compounds are metal compound phases formed between rare-earth metals and other metals or similar metals. They mainly use the special physical and chemical properties of rare-earth intermetallic compounds to prepare new rare earths for various purposes using various processing and manufacturing techniques. Functional Materials. At present, there are the following rare earth metal intermediate compounds with large market demand and industrialization and large-scale production:
(1) SmCo5, Sm2Co7, Nd2Fe14B and Sm2Fe17Nx etc.
Inter-rare earth compounds are rare earth permanent magnet materials with excellent magnetic properties and can be divided into sintered permanent magnets and bonded permanent magnets. Samarium-cobalt permanent magnetic materials have good high-temperature stability and anti-corrosion performance, and the devices mainly used for making traveling waves and circulators have obtained important applications in military and aerospace fields. Samarium iron-nitrogen bonded magnets have a lower rare earth content than neodymium-iron-boron magnets. The Curie temperature is about 740K. The room temperature anisotropy is about 15-16T, which is higher than NdFeB. The oxidation resistance and corrosion resistance of samarium iron-nitrogen are better than NdFeB magnets are expected to have good market prospects.
NdFeB is widely used, including high-tech fields, traditional and general civilian low-end magnets. NdFeB magnets are mainly used in high-tech fields such as electronics, computers, and medical treatment. Among them, VCM, MRI, and various types of motors / generators are mainly used. Applications include CD pickups, CD storage, DVD storage, mobile phones, and cordless electric drives. Tools, electric bicycles, electric mopeds and electric vehicles. In recent years, electric bicycles have developed rapidly, and their driving uses DC NdFeB permanent magnet motors, each of which uses 380g of sintered magnets.
2) RENi5 hydrogen storage alloy. AB5 type MM-Ni-Co-Al-Mn mixed rare earth multi-element alloy, the mixed rare earth content in the alloy accounts for about 34%. Hydrogen storage alloy is used as a negative electrode material in nickel-metal hydride batteries. It has the characteristics of high energy density, long life, no memory effect, excellent large current discharge characteristics and fast charging. It is widely used, mainly used as portable household appliances, digital cameras, notebooks The demand for computers, portable power tools and power sources for hybrid vehicles or electric vehicles is in great demand. In addition, rare earth hydrogen storage alloys have other application prospects, such as hydrogen storage devices for hydrogen storage devices for hydrogen fueled cars and portable small power supply fuel tanks. Using the chemical reaction heat of the hydrogen storage alloy to make a heat pump system is expected to be used in freon-free refrigerators.
(3) TbDyFe giant magnetostrictive material. Compared with traditional magnetostrictive materials, rare earth giant magnetostrictive materials have the characteristics of large magnetostriction coefficient, large stress, low voltage current drive, small hysteresis, fast response and large magnetomechanical coupling coefficient. Rare earth giant magnetostrictive materials can be applied in a wide range of fields. At present, they are mainly used in the production of underwater acoustic transducers and electroacoustic transducers. Vibration control system, marine exploration and underground communication and other fields. Giant magnetostrictive materials are also used to manufacture intelligent vibration aging devices, ultrasonic transducers, sensors and precision actuators.
(4) TbFeCo rare earth-iron group metal amorphous thin film magneto-optical material The rare earth iron amorphous film has the characteristics required for magneto-optical disk storage, that is, the magnetization direction is perpendicular to the film surface, the magnetic domain is stable, the coercive force at room temperature is large, the Curie temperature must be within 100-200 ℃ and the magneto-optic Kerr rotation angle Or the Faraday rotation angle must be large. Magneto-optical discs have the advantages of both magnetic recording and magnetic disk systems, and can be used for advanced audio recorders, optical video recorders, computers, and information archiving.
