Magnet Magnetization Method Guide

Classification of magnetic materials

Most of the magnets currently used on the market belong to permanent magnets, which are divided into two main categories:

1. metal alloy magnets: neodymium iron boron magnets, samarium cobalt magnets, alnico magnets.

2. Ferrite permanent magnets.

How are magnets magnetized?

1. Electromagnetic Magnetization

This is one of the most common methods of magnetization. In the electromagnetic magnetization method, a magnet is placed in a solenoid coil, which is a hollow cylinder in which magnets of different sizes and shapes can be placed, and the coil is energized to produce a strong magnetic field, which magnetizes the magnetic material in order to maintain magnetism.

In order to avoid handling and assembling magnets under magnetized conditions, it is sometimes possible to assemble the magnetic material and then magnetize it. This approach is referred to as post-magnetization of the whole.

• Contact Magnetization

In contact magnetization, a strong magnet (usually a permanent magnet) that has been magnetized is placed in direct contact with the magnet to be magnetized. Through contact, the magnetic material is rearranged in a strong magnetic field and acquires magnetic properties.

• Vibrational Magnetization

In vibrational magnetization, a magnet is placed in a specific device that vibrates at a specific frequency and amplitude. This vibration causes the magnetic material of the magnet to align in vibration, resulting in magnetization.

Regardless of the method used, the magnetization process of the magnet requires strict control of the strength, direction and time of the magnetic field to ensure consistency and quality of the magnetization effect. The magnetized magnet should be tested and inspected to ensure that it meets the specified magnetic performance requirements. And among the different magnetizing methods, electromagnetic magnetization usually provides the greatest magnetic properties.

The most important thing to note about magnetization is the direction of magnetization

Magnetization orientation: generally divided into three types: monopole magnetization, multi-pole magnetization, Helbeck array magnetization.

1. Unipolar magnetization

Mainly includes: axial magnetization, radial magnetization, thickness direction magnetization, axial multi-stage magnetization, inner circle radial magnetization, radiation magnetization, and so on.

Unipolar magnetization is to use the existing magnetizing machine and magnetizing fixture to magnetize the magnetic material, and the magnetized product shows N and S poles (i.e., there is only one pole on one side).

2. Multi-Pole Magnetization

Multi-pole magnetization is the use of customized magnetizing fixtures for magnetization, after magnetization there are more than two pairs of N,S poles on the same magnet (one face with multiple poles).

3. Halbacharray Magnetization

Halbacharray is a magnet assembly structure that is an engineered magnetic field that approximates an ideal structure. The permanent magnets permanent magnets are arranged in different magnetization directions in such a way that the magnetic field on one side of the array is significantly enhanced while the field on the other side is significantly weakened. The goal is to produce the strongest magnetic field in the working area with the least amount of magnetic field.

Three common types of magnetization

1. Unsaturated magnetization: When magnetizing magnetic materials, the magnetizing energy is less than 95% of the saturation magnetization, this way of magnetization is reversible, with the time and the joint action of the external magnetic force, the magnet’s remanent magnetism will gradually decline, this way of magnetization is only used in special work occasions, generally do not use this way of magnetization.

2. saturation magnetization: in the magnetization of magnetic materials, the magnetizing energy to reach the magnetic material, the magnetization characteristics of the inflection point of the energy required, generally for the magnetic material endowed with coercive force of 1.5 times -2 times, the smallest generally take 2 times, the way this magnetization can be made to achieve the saturation of the magnetization, demagnetization phenomenon will not occur under normal circumstances.

3. oversaturation magnetization: when magnetizing magnetic materials, the magnetizing energy exceeds the energy required for the inflection point of the magnetization characteristics of the magnetic material, generally 3 times the endowed coercivity of the magnetic material, because of the characteristics of the magnetic material, the surface magnetic field of the magnet is saturated, and the strength of the external magnetic field will only have a small amount of change in the magnetic material. In general, this type of magnetization is generally used in environments with high magnetic energy requirements.