(1) bonded NdFeB
Bonded NdFeB is a composite NdFeB permanent magnet made by mixing NdFeB powder with binder such as resin, plastic or low melting point metal, and then pressing, extruding or injection molding. Products can be molded once without secondary processing, and can be directly made into various complex shapes. Bonded NdFeB is omni-magnetic, and can be processed into NdFeB die and injection molding. High precision, excellent magnetic properties, good corrosion resistance and good temperature stability.
(2) sintering NdFeB
Sintered NdFeB permanent magnet is smelted after jet grinding, which has high coercivity and extremely high magnetic properties, and its maximum magnetic energy product (BHmax) is more than 10 times higher than that of ferrite. Its own mechanical properties are also quite good, and it can cut and process different shapes and holes. The highest working temperature of high-performance products can reach 200℃.
Because its material composition is easy to cause corrosion, the surface must be treated at different levels according to different requirements. (such as zinc plating, nickel, environmental protection zinc, environmental protection nickel, nickel copper nickel, environmental protection nickel copper nickel, etc.). ). Very hard and brittle, strong demagnetization resistance, high cost performance, not suitable for high working temperature (> 200℃).
(3) NdFeB injection molding.
It has high accuracy and is easy to make anisotropic thin-walled rings or thin magnets with complex shapes. The main raw materials of sintered ferrite are BaFe 120 19 and SrFe 120 19, which can be divided into isotropic and anisotropic magnets according to the orientation of magnetic crystals.
Because of its low price and moderate magnetism, it has become a widely used magnet at present. Ferrite magnet is made of ceramic technology, which is hard and brittle. Because of its good temperature resistance and low price, ferrite magnet has become a widely used permanent magnet. SmCo can be divided into SmCo5 and Sm2Co 17, which are the first and second generation rare earth permanent magnet materials respectively. Because its raw materials are scarce and expensive, its development is limited. As the second generation rare earth permanent magnet, SmCo not only has high magnetic energy product (14-28MGOe) and reliable coercivity, but also shows good temperature characteristics in rare earth permanent magnet series. Compared with NdFeB, samarium cobalt is more suitable to work in high temperature environment (>: 200℃).