The Orientation And Magnetization Direction Of Magnet

Magnetization is an essential process in the production of magnet. If a magnet is not magnetized, it will not possess magnetism and lose its basic function as a permanent magnet. As a three-dimensional workpiece, magnet has different shapes and sizes. How to magnetize magnet? Is the magnetization effect the same in different directions? Today we will talk about these issues.

The direction of magnetization depends on the orientation direction

Determine the direction of easy magnetization based on the orientation direction, and only along the direction of easy magnetization can the magnet reach saturation with the minimum energy. What is orientation? Orientation is actually magnetization, but during the production and forming process of magnet, pre-magnetization is applied to the magnetic powder that has not been finally densified or to the alloy that has not been finally formed during heat treatment, so that the magnetic domains are arranged as uniformly as possible along the direction of the magnetization field. The higher the arrangement degree, the better the orientation degree, and the higher the residual magnetism of the magnet. Orientation can be simply considered as road construction, similar to laying a north-south direction highway. Vehicles can only travel south or north and cannot move in other directions. The magnetic domains after orientation are also arranged in both directions, that is, if they are oriented vertically, they can only be magnetized in the vertical direction, which can be up ‘N’ and down ‘S’, or up ‘S’ and down ‘N’.

According to whether there is an orientation link in the production process of magnet, permanent magnet materials can be divided into two categories. Among them, oriented materials are called anisotropic materials (also known as heteroscedasticity), and unoriented materials are called isotropic materials (also known as isotropy). The magnetism of anisotropic materials is stronger than that of isotropic materials. The residual magnetism of isotropic materials can only reach up to half of anisotropy, and the magnetic energy product can only reach up to a quarter of anisotropy. However, the intrinsic coercivity of isotropy is higher than that of anisotropy, and the demagnetization curve of anisotropy has better squareness, while that of isotropy is poorer.

For anisotropic magnet, due to the ordered arrangement of magnetic domains after orientation, magnetization must be on the same axis or dimension as the orientation direction, as shown in the following figure. Highly oriented magnet can be magnetized in the form of up ‘N’ and down ‘S’ or up ‘S’ and down ‘N’, or in many combinations of up ‘N’, down ‘S’, and up ‘S’ and down ‘N’.

Isotropic magnets are unoriented, meaning that the magnetic domains are randomly arranged. Although their performance is not high, they can be magnetized in all directions, depending on the type of magnetic field applied. Therefore, just like a large number of isotropic bonded neodymium iron boron rings made of radiation multipole rings, as long as the magnetization clamp can make the magnetization method, the magnet can be magnetized, as shown in the following figure.