Neodymium magnet（Neodymium magnet）Also known asNeodymium iron boron magnet（NdFeB magnet）, is byneodymium、iron、boron(Nd2Fe14B)Tetragonal systemCrystal.In 1982,Sumitomo Special MetalOfSagawa ImmortalNeodymium magnets were found.The magnetic energy product (BHmax) of this magnet is greater thanSamarium cobalt magnetIt was the material with the largest magnetic energy product in the world at that time.Later,Sumitomo Special MetalSuccessful developmentPowder metallurgy（powder metallurgy process），General MotorsSuccessful developmentRotary jet melting process(melt spinning process), which can be preparedNeodymium iron boron magnet。This magnet is second only to the absolute zero holmium magnetPermanent magnet, which is also the most commonly usedRare earth magnet。Nd-Fe-B magnets are widely used in electronic products, such asHard disk、mobile phone、headsetAnd usingBatteryPower supply tools, etc.
Neodymium magnet（Neodymium magnet）Also known asNeodymium iron boron magnet（NdFeB magnet）, is byneodymium、iron、boron（NdtwoFefourteenB) FormedTetragonal systemcrystal。In 1982,Sumitomo Special MetalOfSagawa ImmortalNeodymium magnets were found.The magnetic energy product (BH) of this magnetmax）Greater thanSamarium cobalt magnetIt was the material with the largest magnetic energy product in the world at that time.Later,Sumitomo Special MetalSuccessful developmentPowder metallurgy（powder metallurgy process），General MotorsSuccessful developmentRotary jet melting process(melt spinning process), which can prepare Nd-Fe-B magnets.This magnet is second only to the absolute zero holmium magnetPermanent magnet, which is also the most commonly usedRare earth magnet。Nd-Fe-B magnets are widely used in electronic products, such asHard disk、mobile phone、headsetAnd usingBatteryPower supply tools, etc.
for fear ofcorrosionThe surface of permanent magnetic materials needs to be protected during use, such asgold、nickel、zinc、tinPlating and surface sprayingepoxy resinEtc.
classification
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Nd-Fe-B is divided into sintered Nd-Fe-B andbonded NdFeB Two, bonded Nd-Fe-B is magnetic in all directions and corrosion resistant;Sintered Nd-Fe-B is easy to corrode, so its surface needs coating, generally including zinc plating, nickel, environmental zinc, environmental nickel, nickel copper nickel, environmental nickel copper nickel, etc.But sintered Nd-Fe-B is generally divided into axial directionsMagnetizationAnd radial magnetization, depending on the required working surface.
NdFeB surface treatment:
NdFeB
With the unfreezing of the patent technology of sintered Nd-Fe-B in Japan, Germany and the European Union, and the concerted efforts of major sintering manufacturers in China, the grade of sintered Nd-Fe-B products has been greatly improved. As a high-tech application field, the continuous improvement of its comprehensive performance has also greatly improved the requirements for its sintered Nd-Fe-B surface treatment, and the traditional treatment methods have been unable to meet the requirements of the progress of the industrial chain. UESTC,Scientific research institutions such as Sichuan University, Jiaotong University and Ruishiles have made breakthroughs in key technologies after four years of efforts to improve the principle of surface treatment and the development of industrial application processes in essence from the perspective of micro molecular structure. Nanometer (3010) chelating film is treated without coating, which is an original technology process. The active groups contained in the nano film have strong resistance to moisture, oxygen and chloride ions (Cl),Carbon dioxide (CO2), etc. Corrosion resistance and adhesive ability of organic resin have been greatly improved. Its excellent surface physical and chemical properties will have a significant impact on the application field
In December 2013, the treatment process was systematically tested by Sichuan University and the Chinese Academy of Sciences. Its corrosion resistance meets the requirements of 20-30 years of use in marine climate conditions, and can be widely used in sea based wind power generation. The surface bonding force is above 20Mpa, and can be widely used in permanent magnet high-speed motors, special motors, electric vehicle motors, ultra-high voltage, high-voltage DC power supply systems, rapid charging systems, aerospace and military industries and other fields.
Common surface treatment methods:
1. Nano (Royce3010) chelating film without coating treatment;(3010 means that the film contains more than three active chelating groups, and the film thickness is 10 nm);
2, phosphating;
3. Electroplating;
4, electrophoresis;
5. Vacuum vapor deposition;
6. Electroless plating;
7. Organic spraying;[1]
application
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3010 section scanning electron microscope
Sintered Nd-Fe-B permanent magnetic materials have excellent magnetic properties, and are widely used in electronics, electrical machinery, medical devices, toys, packaging, hardware machinery, aerospace and other fields. Permanent magnet motors, loudspeakers, magnetic separators, computers are more commondisc driveMagnetic resonance imaging equipment and meters.
Nanometer (Royce3010) chelating film coating free treatment can meet the requirements of 20-30 years of use in marine climate conditions, and can be widely used in sea based wind power generation. The surface bonding force is more than 20Mpa, which can be widely used in permanent magnet high-speed motors, special motors, electric vehicle motors, ultra-high voltage, high-voltage direct current power supply systems, rapid charging systems, aerospace military industry and other fields.[1]
chemical composition
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NdFeB Permanent magnetic materialIt is a permanent magnetic material based on the intermetallic compound Nd2Fe14B.The main component is rare earth element neodymium（iron（Fe）、boron（B）。The rare earth elements are mainlyneodymium(Nd), Dypraseodymium(Pr) and other rare earth metals, and iron can also be partially replaced by cobalt (Co), aluminum (Al) and other metals. The content of boron is small, but it plays an important role in the formation of tetragonal crystal structure intermetallic compounds, making the compounds have highSaturation magnetization, high single shaftanisotropyAnd highCurie temperature。
The third generation of rare earth permanent magnet Nd-Fe-B is the strongest permanent magnet among contemporary magnets. Its main raw materials are rare earth metal Nd 29% - 32.5% metal element Fe 63.95-68.65% non-metal element boron 1.1-1.2%, dysprosium 0.6-8% niobium 0.3-0.5% aluminum 0.3-0.5% copper 0.05-0.15% and other elements.
distinguish
1. It is usually placed on a plane that can be adsorbed with a magnet of the same specification, such as patch, blade, iron door, etc., and the magnetic force can be identified by hand feeling
2. Use an electronic scale: a magnet with weak magnetic force is generally related to its density. If the density is small, the magnetic force is relatively small. If the weight is heavy, the magnetic force is relatively large. On the contrary, if the weight is light, the magnetic force is small. If the requirements for the magnet are high, the instrument test is required.[1]
The grades of Nd-Fe-B magnetic materials include N35-N52, 35M-50M, 30H-48H, 30SH-45SH, 28UH-35UH, 28EH-35EH.
Grade example: 048021 means sintered Nd-Fe-B permanent magnet with (BH) max of 366~398kj/m3 and Hcj of 800KA/m.
The brand of sintered Nd-Fe-B permanent magnetic material consists of the main name and two kinds of magnetic properties. The first part is the main name and consists ofNeodymium elementThe chemical symbol ND for iron and the chemical symbol FE for boronChemical symbolB composition, the second part is the figure in front of the line, which is the nominal value of the maximum magnetic energy product (BH) max of the material (unit: kj/m3), and the third part is the figure behind the oblique line, which is the magnetic polarization intensityCoercivityOne tenth of the value in KA/m, rounded to the nearest whole.
Brand example: NdFeb380/800 means sintered NdFeB permanent magnet with (BH) max of 366~398kj/m3 and Hcj of 800KA/MR.
Sintered Nd-Fe-B permanent magnetic materials have excellent magnetic properties and are widely used in electronics, electrical machinerymedical apparatus and instruments, toys, packaging, hardware machinery, aerospace and other fields, such as permanent magnet motors, loudspeakers, magnetic separators, computersdisc driveMagnetic resonance imaging equipment and meters.
Curie temperature
The Curie temperature of ferrite is 465 ℃,
The Curie temperature of Nd-Fe-B is 320 ℃ - 460 ℃,
The Curie temperature of Al Ni Co is 800 ℃,
The Curie temperature of samarium cobalt is 700-800 ℃
Ferrochrome cobalt Curie temperature is 680 degrees
Process flow: batching → smelting and ingot making/belt throwing → milling → molding → sintering and tempering → magnetic testing → grinding → pin cutting → electroplating → finished products.Among them, batching is the basis and sintering tempering is the key.
Production tools and performance testing tools for Nd-Fe-B magnet blanks: smelting furnace, belt throwing furnace, jaw crusher, air flow mill, press forming machine, vacuum packaging machine, isostatic press, sintering furnace, heat treatment vacuum furnace, magnetic property tester, Gauss meter.
Neodymium iron boron,also known asNeodymium iron boron magnet（NdFeB magnet）, is byneodymium、iron、boron（NdtwoFefourteenB) FormedTetragonal systemCrystal.By Japan in 1982Sumitomo Special MetalOfSagawa Immortal(Masato Sagawa) found neodymium magnet.The magnetic energy product (BH) of this magnetmax）Greater thanSamarium cobalt magnetIs the material with the largest magnetic energy product in the world at that time.Later, Sumitomo Special Metals developed successfullyPowder metallurgy（powder metallurgy process）。General MotorsSuccessful developmentRotary jet melting process(melt spinning process), which can prepare Nd-Fe-B magnets.This magnet is the strongest permanent magnet nowadays, and also the most commonly used rare earth magnet.[1]
