The magnetism of permanent magnet mainly comes from its crystal structure which is easy to be magnetized. It can obtain extremely high magnetism under the action of external strong magnetic field, and its magnetism will not disappear after the external magnetic field disappears. Therefore, "magnetization" is a key step for permanent magnet materials such as NdFeB to obtain magnetism.
Isotropic magnets and anisotropic magnets
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 drawn together arbitrarily. Anisotropic magnets have different magnetic properties in different directions, and the direction in which they can obtain the best magnetic properties is called the orientation direction of the magnet.
In the production process of magnetic materials, if there is orientation process, it is anisotropic magnet. Sintered NdFeB magnets are generally pressed with magnetic field orientation, so it is necessary to determine the orientation direction and the coming direction of magnetization before production. Powder magnetic field orientation is one of the key technologies for manufacturing high performance NdFeB.
Direction of magnetization
Magnetization is the process by which a magnetic field is applied to a permanent magnet along the direction of the magnetic field, gradually increasing the strength of the magnetic field until it reaches technical saturation. Sintered NdFeB magnets generally have square, cylindrical, ring, tile and other forms, next we will talk about their common direction of magnetization.
In addition to the ordinary monopole magnetization, sintered NdFeB ring magnet can also be multi-pole magnetization according to the actual needs, that is, after magnetization can present a number of N, S poles on a plane. Due to the use of specially designed size and pole head magnetizing fixture, additional magnetizing fixture costs will be incurred。
Method of magnetization
Magnetometer is a tool for magnetizing and magnetizing magnetic materials or magnetic device magnets, through which magnetic field is applied to the permanent magnet products that need to be magnetized. If the magnetizing magnetic field cannot reach the technical saturation magnetic field, the remanence Bj and coercivity Hcj of the permanent magnet cannot reach the required values. So how do we determine the energy of the magnetometer? First, determine the size and size of the magnetizing tooling according to the size and direction of the magnetizing product magnet, then calculate the size of the tooling central magnetic field, the size of the tooling magnetic field should be 3-5 times the magnetic force of the magnet, finally calculate the magnetizing current, according to the current and the voltage of the magnetizing machine finally determine the energy storage capacity of the magnetizing machine, and finally determine the energy of the magnetizing machine.
The basic principle of magnetization is to magnetize the magnetic object can be placed in the magnetic field formed by the coil of direct current through the way of DC magnetization and pulse magnetization.