Magnetic power energy requirements for magnetic materials

- Apr 20, 2019-

Regular arrangement of molecules of magnetic materials and requirements for magnetic power energy

 

We know that the arrangement of ordinary magnetic fields inside and outside a magnet is very simple. It is generally accepted that the lines of magnetic force start from the N pole and go back to the S pole. Therefore, the distribution of magnetic field lines in the outer space of the magnet is very regular. It is generally accepted that the line of magnetic force from the N pole can be regarded as perpendicular to the surface of the pole when it first leaves the pole. However, such a magnetic field must be treated in a special way to be applied to magneto dynamic energy. In other words, the line of magnetic force is not perpendicular to the magnetic pole when it leaves the surface of the magnet.

The direction of the magnetic field line on the magnetic pole surface and the Angle of the magnetic pole surface are not 90 degrees. Such a magnetic field is not easy to realize. There are mainly the following reasons:

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One reason is that the processing method is difficult:

Generally, we use materials with high magnetic conductivity as the magnetic source of magnetized magnet. Objects with high magnetic conductivity have a magnetic field that is perpendicular to the surface. This is caused by its conduction to the magnetic field.

When we magnetize the magnet, we usually use the method of electromagnet. An iron rod at the center of the coil creates a strong magnetic field. We can use the very high permeability of ferromagnetic materials to produce very high magnetic fields between the two magnetic poles.

In general, at the center of two magnetic poles, the magnetic line of a magnet can be regarded as strictly perpendicular to the surface of the poles. In the process of magnetizing a magnet, materials with very high magnetic conductivity are used as magnetic sources, and it can be considered that the magnetic field is mainly conducted by materials with very high magnetic conductivity. This requires that the surfaces of the two poles of the two sources must be particularly smooth and flat, with no bumps or depressions.

This only means that the internal molecular structure of the alloy magnet is not uniform, which contains the free state of the material with high magnetic conductivity. When two magnets are far away from each other, the free material inside the magnet will strengthen the external magnetism of the magnet. But when the distance is relatively close, the free state of the material with high magnetic conductivity will be affected by the external magnetic field, or even change the direction of magnetization due to the effect of the external magnetic field, so that the phenomenon of phase suction.


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If the shape of the magnet is like the picture above, you might think that the direction of the magnetic field line and the surface of the magnetic pole are not equal to 90 degrees. No, it turns out that the direction of the magnetic field line is still 90 degrees from the surface of the magnetic pole. If we use such a device to magnetize a magnet that needs to be magnetized, the direction of the magnetic field line we get is still perpendicular to the surface of the magnetic pole. This is because the N and S surfaces in the figure are materials with high magnetic conductivity, and the magnetic field direction of NS pole is still perpendicular to the N and S surfaces.

 

The second reason is that in addition to having a specific shape, we need magnets that do not contain a high permeability free state of high permeability material.

 

Now science and technology about permanent magnet has been a great development. In practical technical applications, many fields are usually used alloy magnets, such as iron cobalt nickel, aluminum cobalt nickel and so on. We often see a phenomenon: two alloy magnets repel each other when they are far apart, but when we pull the two magnets close together, suddenly the two magnets attract. This seems to violate the principle of magnetism. Not really.

 

Although this alloy magnet was very strong when it was first made. But because it contains a free magnetic material, it will change the direction of the magnetic field under the action of the external magnetic field, and the magnetic force will gradually weaken.

 

A third reason is the need for specific molecular structures.

 

So, in order for the magnet to act in a certain direction, it needs a stable distribution of molecular structure. Of course, a crystal like structure is best. The external effect of the whole will not change the direction of the magnetic field due to the presence of local external effect on itself. Or the direction of the magnetic field changes within the permissible range. This requires stable intermolecular interactions.

One of the parameters of a magnet is called Hcj. If we want to use the material with high Hcj as the magnet material, it will undoubtedly increase the difficulty of magnetizing the magnet.