Some foreign customers will consult about whether the neodymium magnets could be shipped by air or not. As is known to all, neodymium magnets have very strong magnetism, which might affect electronic equipment if bring them to the airplane. So the magnets need to be demagnetized. The so-called demagnetization, actually the magnets themselves didn’t lose their magnetism, but weaken their magnetism by using permeability magnetic material to change the magnetic field distribution of magnets, that is magnetism isolation packages.
 
Iron sheets are usually used to isolate the magnetism, they are used to fix inside the six sides of the boxes, and then pack the magnets with foam and carton, so as to pass the security check of airline.
 
What is the principle of isolating magnetism?
The principle of isolating magnetism is to shield the magnetic field of magnets, which is mainly about steady-state magnetic field or low frequency magnetic field; it mainly depends on magnetic circuits. If the boxes are made of magnetic mater, the “magnetic lines” that would have gone out of the box are concentrated inside the boxes and form a closure. This greatly reduces leakage of magnetic lines outside the boxes.  
 
What are the general methods of isolating magnetism?
In order to shielding the magnetism, it would be better if the material has a high magnetic permeability. With same material, thicker is better. With same material and same thickness, the more layers, the better. Besides, to avoid the magnetic lines will be concentrated on one side and leak out more, the strong neodymium magnets should be put in the center of shielding box. Second, material will be magnetized. The permeability magnetic material is always magnetized in the magnetic field. But except hard magnetic material, the magnetism will be immediately eliminated once external magnetic field is removed. Therefore, if the shielding material is made from hard magnetic material and form a new independent magnetic field, it will influence the shield effects. That’s the reason why we can only use soft magnetic material as shielding material.
 
 
If you ask now that the soft magnetic material also can be magnetic in the magnetic field, so how it isolate the magnetism? This is because the resulting new magnetic field strength completely changes according to the external original magnetic field strength when the soft magnetic material is magnetized. Then according to the principle of high frequency magnetic field shielding, achieve the shielding effect by magnetic mutual offset.
 
Are you clear about it? Eliminating the magnetism is only to put a layer of material that can isolate magnetism outside the neodymium magnets, which doesn’t have any influences on magnets themselves.
 
Tags: neodymium magnets, strong magnets