Basic knowledge of NdFeB magnet

- Jul 19, 2019-

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Ndfeb magnetic material, as the latest result of rare earth permanent magnet material development, is called "magneto" because of its excellent magnetic properties. Ndfeb magnetic material is an alloy of neodymium, iron oxide, etc. Also known as magnetic steel. Neodymium iron boron material contains a lot of neodymium and iron, easy to rust. So ndfeb magnets must be coated on the surface. Surface chemical passivation is one of the best methods.


Neodymium iron boron has extremely high magnetic energy and force, at the same time the advantages of high energy density neodymium iron boron permanent magnet material in modern industry and electronic technology has been widely used, so that instruments, electro-acoustic motors, magnetic separation magnetization and other equipment miniaturization, lightweight, thin become possible. Ndfeb has the advantages of high cost performance and good mechanical characteristics. The shortcomings are low Curie temperature point, poor temperature characteristics, and easy to powder corrosion, which must be improved by adjusting its chemical composition and adopting surface treatment methods to meet the requirements of practical application. Ndfeb is divided into sintered ndfeb and bonded ndfeb two, bonded ndfeb in all directions are magnetic, corrosion resistance; Sintered ndfeb due to corrosion, surface coating, generally galvanized, nickel, environmental protection zinc, environmental protection nickel, nickel copper nickel, environmental protection nickel copper nickel.


And sintered ndfeb is generally divided into axial and radial magnetization, according to the need to work face. Chemical composition: ndfeb permanent magnet material is based on intermetallic compound RE2FE14B. The main components are RE, FE and B. Part of rare earth ND for different performance available dysprosium (Dy), praseodymium (Pr), and other rare earth metals replace, iron can also be cobalt (Co), aluminum (Al) and other metal parts replacement, boron content is smaller, but to form a square crystal structure between the metal compounds play an important role, yes compounds with high saturation magnetization, high uniaxial anisotropy and high Curie temperature. Brand: each product is divided into several brands according to the maximum magnetic energy product size. Ndfeb magnetic materials are: N35 -- N52,N35M -- N50M, N30H -- N48H,N30SH -- N45SH.


N28UH - N35UH N28EH - N35EH. Digital brand, example brand: 048021 means (BH) Max is 366~398kj/m3, Hcj is 800KA/m sintered ndfeb permanent magnet material. Character of sintered ndfeb permanent magnet material grades by the main ChenHe two magnetic properties of three parts, the first part is given priority to, according to the chemical symbol ND of neodymium, iron chemical symbol of FE and boron element, chemical symbol B, the second part is the line in front of the Numbers, is the material nominal value of the maximum magnetic energy product (BH) Max (in kj/m3), the third part to slash the number, the intensity of magnetic polarization coercive force value (unit for KA/m), one over ten of numerical adopts the nearest integer. Example: ndfeb380/80 means that (BH) Max is 366~398kj/m3 and Hcj is 800KA/MR sintered ndfeb permanent magnet.




Application: sintered ndfeb permanent magnet material has excellent magnetic properties, widely used in electronics, power machinery, medical equipment, toys, packaging, hardware machinery, aerospace and other fields, more common permanent magnet motor, speakers, magnetic separator, computer disk drive, magnetic resonance imaging equipment and meters. Medical treatment: ndfeb permanent magnet (strong magnet) is the national 863 project plan project high-tech materials. What he can produce is a kind of biological magnetic field that simulates the magnetic field characteristics of human body, with stable performance!