Magnetization is a necessary process in the production of magnets, if the magnet is not magnetized, it does not have magnetic properties and loses its basic function as a permanent magnetic material. This article will talk about the magnetization.
Magnetization is the process of making a ferromagnetic substance temporarily or permanently magnetic, as by insertion in a magnetic field. Different magnetic materials require different methods of magnetization.
Magnetization Direction
Magnetic materials are divided into two categories: isotropic and anisotropic magnets. Isotropic magnets have the same magnetic properties in any direction. Anisotropic magnets have different magnetic properties in different directions. The direction in which the strongest magnetic properties are obtained is called the orientation of the magnet.
The main magnetization directions include axial magnetization direction, diametrical magnetization direction, radial magnetization direction, and so on.
Generally speaking, thinner magnets are magnetized in the axial direction, while those with a thickness greater than the diameter are magnetized in the radial direction. The smaller the magnet diameter, the more difficult it is to magnetize.
Magnetization Effect
There are three kinds of magnetization effects, that is, unsaturated magnetization, saturation magnetization, and oversaturated magnetization.
Unsaturated Magnetization | When magnetizing magnetic materials, the magnetizing energy is less than 95% of the saturation magnetization. With the combined effect of time and external magnetic force, the remanence of the magnet will gradually decline. Unsaturated magnetization is only used in special environments, and this way of magnetization will not be used in general.
Saturation Magnetization | The general rule is that to saturate magnetic materials, the magnetizing energy peak must reach 1.5 times to 2 times the intrinsic coercivity of the magnetic materials. For example, an Hci of 20,000 Oersteds will require at least 40,000 Oersteds to saturate. This magnetization method can make the magnet reach saturation magnetization and demagnetization will not occur under normal circumstances.
Oversaturated Magnetization | When magnetizing magnetic materials, the magnetizing energy reaches 3 times the intrinsic coercivity of the magnetic material. If the customer requires higher magnetic performance of the magnet, generally use this method for magnetizing magnets.
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Magnetizing Machine
A magnetizing machine is a tool for magnetizing magnets or magnetic assemblies. If the magnetic field for magnetization does not reach the saturation magnetic field, the remanence (Br) and the intrinsic coercivity (Hcj) of the permanent magnet will not achieve the desired values.
Before the magnetization, the magnitude of the magnetizing field is calculated according to the magnet size, magnetization direction, and other information. Generally speaking, the magnetizing field should be 3-5 times the coercivity of the magnet. The next move is to calculate the magnetizing current and the capacity of the storage capacitor of the magnetizing machine will be determined according to the current and the voltage of the machine. Finally, the magnetization is started.
Kinds of Magnetizing Machine
Constant Current Magnetizing Machine | When a constant direct current passes through the coil, a constant magnetic field is generated. It usually produces a magnetic field of only 2 MA/m and is suitable for magnets with low coercivity, such as ferrite magnets.
Pulse Magnetizing Machine | The principle of pulse magnetization is to pass an instantaneous pulsed high current through the coil so that the coil produces a super-strong magnetic field. This method of magnetization is suitable for high-coercivity permanent magnets, such as neodymium magnets, or complex multi-pole magnetization.
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Magnets Manufacturer-Tengye
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