The magnetic properties of sintered NdFeB materials mainly come from their easily magnetized crystal structure, which can obtain extremely high magnetism under the action of strong external magnetic field, and its magnetism will not disappear after the external magnetic field disappears, so “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 and the upcoming magnetization direction have been determined when the magnetic powder is pressed into the blank.
- Magnetic field orientation
Magnetic materials are divided into two categories: isotropic magnets and anisotropic magnets. The magnetic properties of isotropic magnets in any direction are the same, and they can be drawn together arbitrarily; Anisotropic magnets have different magnetic properties in different directions, and the direction in which the best magnetic properties can be obtained is called the orientation direction of the magnet. A square sintered NdFeB magnet has the largest magnetic field strength only in the orientation direction, and the magnetic field strength in the other two directions is much smaller.
If there is an orientation process in the production process of magnetic materials, it is an anisotropic magnet, and sintered NdFeB is generally formed and pressed by magnetic field orientation, so it is anisotropic, so it is necessary to determine the orientation direction before production, and the upcoming magnetization direction. Powder magnetic field orientation is one of the key technologies for the manufacture of high-performance NdFeB. (Bonded NdFeB is both isotropic and anisotropic)
- Magnetization direction and method
Magnetization is the process of applying a magnetic field to a sintered NdFeB permanent magnet in the direction of the magnetic field, and gradually increasing the strength of the magnetic field to reach the state of technical saturation.