Magnetic Field Orientation and Magnetization of Sintered NdFeB

The magnetism of sintered NdFeB materials mainly comes from their easily magnetized crystal structure. They can obtain extremely high neodymium magnet grades under the action of a strong external magnetic field, and their magnetism will not disappear after the external magnetic field disappears. Therefore, "magnetization" is a key step for sintered NdFeB materials to obtain magnetism. In the production and preparation process of sintered NdFeB materials, magnetization is the last step before the delivery of the finished product, but the magnetic field orientation of the NdFeB blank, that is, the future magnetization direction, has been determined when the magnetic powder is pressed into a blank.

Magnetic field orientation

Magnetic materials are divided into two categories: isotropic magnets and anisotropic magnets. Isotropic magnets have the same magnetic properties in any direction and can be attracted together at will; anisotropic magnets have different magnetic properties in different directions, and the direction that can obtain the best magnetic properties is called the orientation direction of the magnet. For a square sintered NdFeB magnet, only the magnetic field intensity in the orientation direction is the largest, and the magnetic field intensity in the other two directions is much smaller.

If the magnetic material has an orientation process during the production process, it is an anisotropic magnet. Sintered NdFeB is generally formed and pressed by magnetic field orientation, so it is anisotropic. Therefore, the orientation direction, that is, the future magnetization direction, needs to be determined before production. Powder magnetic field orientation is one of the key technologies for manufacturing high-performance NdFeB.

Magnetization direction and method

Magnetization is the process of applying a magnetic field to the sintered NdFeB permanent magnet along the magnetic field orientation direction and gradually increasing the magnetic field strength to reach the technical saturation state.

Sintered NdFeB generally has several shapes such as square, cylindrical, ring, tile, etc. It is generally divided into single-pole and multi-pole magnetization. After multi-pole magnetization, multiple N and S poles can be presented on one plane.