Neodymium iron boron powder: what is it? how does it work?

Neodymium magnet (Neodymium magnet), also known as NdFeB magnet (NdFeB magnet), is a tetragonal crystal system formed by Neodymium, iron and boron (Nd2Fe14B). In 1982, Shinjin Sagawa of Sumitomo Special Metals discovered neodymium magnets. The magnetic energy product (BHmax) of this magnet was larger than that of samarium cobalt magnet, and it was the largest magnetic energy product of any substance in the world at that time. 

Later, Sumitomo developed a powder metallurgy process for special metals, and General Motors developed melt-smelting process, able to produce ND-Fe-B magnets. This magnet is now the second most magnetic permanent magnet to absolute zero holmium magnets, and is the most commonly used rare-earth magnet. Ndfeb magnets are widely used in electronic products such as hard disks, mobile phones, headphones and battery-powered tools.

In order to avoid corrosion damage, it is necessary to do protective treatment on the surface of permanent magnet materials, such as electroplating with gold, nickel, zinc, tin, and coating epoxy resin on the surface.

The chemical composition of NdFeB powder

Ndfeb permanent magnet material is a permanent magnet material based on intermetallic compound Nd2Fe14B. The main components are rare earth elements neodymium (Nd), iron (Fe) and boron (B). Of rare earth elements mainly for neodymium (Nd), in order to obtain different performance available parts of dysprosium (Dy), praseodymium (Pr), and other rare earth metals, 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, the compounds with high saturation magnetization, High uniaxial anisotropy and high Curie temperature.

The third generation of rare earth permanent magnet NdFeb is the most powerful permanent magnet in the contemporary magnet. Its main raw materials are rare earth metal neodymium 29%-32.5% metal element iron 63.95-68.65% non-metallic element boron 1.1-1.2% add dysprosium 0.6-8% niobium 0.3-0.5% aluminum 0.3-0.5% copper 0.05-0.15% and other elements.

The discrimination of neodymium iron boron powder

1. Usually with a magnet of the same specification placed on a surface that can be adsorbed, such as: patch, blade, iron door, etc., with the feel to identify the size of the magnetic force.

2. Use electronic scale: the weak magnetic force of the magnet is generally related to its density. If the density is small, the magnetic force is relatively small, and the weight is heavy, the magnetic force is relatively large. On the contrary, the light magnetic force is small.

Classification of neodymium magnet powder

Ndfeb is divided into sintered NdFeb and bonded NdFeb. Bonded NdFeb has magnetic and corrosion resistance in all directions; And sintered NdFeb is easy to corrosion, the surface needs coating, generally galvanized, nickel, environmental protection zinc, environmental protection nickel, nickel copper nickel, environmental protection nickel copper nickel and so on. The sintered NdFeb is generally divided into axial and radial magnetization, according to the required working face.

NdFeB surface treatment

With the thawing of the patent technology of the NdFeb of Japan, Germany and the European Union, the concerted effort of each sintering factory in our country, the grade of sintered NdFeb product has been greatly improved. As the continuous improvement of its comprehensive performance in the field of high-tech applications, the requirements for the surface treatment of sintered Ndfeb have been greatly increased, and the traditional treatment methods have been unable to meet the requirements of industrial chain progress. 

The University of Electronic Science and Technology, Sichuan University, Jiao Tong University, Reissles and other scientific research institutions, starting from the microscopic molecular structure, from the essence of the surface treatment principle and industrial application process development, after 4 years of efforts and made a breakthrough in key technologies. Nano (3010) chelating film without coating treatment, this technology is an original technology, nano film layer contains active groups with strong resistance to moisture, oxygen, chloride ions (Cl-), carbon dioxide (CO2), etc. Corrosion resistance and organic resin adhesion ability performance greatly improved. Its excellent surface physical and chemical properties will have a great impact on the application field.

In December 2013, the treatment process was tested by Sichuan University and Chinese Academy of Sciences. Its corrosion resistance can be used in Marine climate conditions for 20-30 years, and can be widely used in sea-based wind power generation. The surface bonding force is above 20Mpa, which can be widely used in permanent magnet high-speed motor, special motor, electric vehicle motor, UHV, HVDC power supply system, fast charging system, aerospace and military industry and other fields.

Common surface treatment methods:

1. nanometer (Royce3010) chelating film without coating treatment; (3010 refers to the membrane layer containing more than three or more active chelating groups, the thickness of the membrane layer is 10 nm);

2. phosphating;

3. electroplating;

4. electrophoresis;

5. true air deposition;

6. electroless plating;

7. organic spray;

Neodymium powder application

Sintered Ndfeb permanent magnet material has excellent magnetic properties, widely used in electronics, electric machinery, medical instruments, toys, packaging, hardware machinery, aerospace and other fields, the most common permanent magnet motor, loudspeaker, magnetic separator, computer disk drive, magnetic resonance imaging equipment instrument and so on.

Nanoscale (Royce3010) chelated films can be used in Marine climate conditions for 20-30 years without coating treatment and can be widely used in sea-based wind power generation. The surface bonding force is above 20Mpa, which can be widely used in permanent magnet high-speed motor, special motor, electric vehicle motor, UHV, HVDC power supply system, fast charging system, aerospace and military industry and other fields.