Magnetic materials play an irreplaceable role in the fields of information, communication, transportation and automation, which have the fastest development and the greatest impact on society. As one of the most important functional materials in today's industrial society, permanent magnet materials have been widely used in computers, loudspeakers, household appliances, instruments and meters, magnetic machinery, various motors, medical instruments and other instruments. China is rare earth kingdom and permanent magnet material production country, is known as the "permanent magnet king" of ndfeb one of the invention. Modern high technology has put forward higher requirements on the performance and quality of permanent magnet, while the third generation permanent magnet (NdFeB) cannot meet these requirements. At present, the development of the fourth generation permanent magnet has not made a major breakthrough. Therefore, under the present conditions, how to improve the magnetic field strength of permanent magnets? Let's do a little experiment.
We all know that when two permanent magnets are placed on the same plane opposite to each other with the same pole and opposite to each other with different poles, the distribution of magnetic sense lines is shown in figure 1 and figure 2 respectively.
For the contact of anisotropic magnetic poles, it is no different from that of a normal single magnet, while the distribution of magnetic sensing lines connected with the same magnetic pole is shown in the figure, and the magnetic sensing lines between the opposite poles are mutually repulsive and radiate outward. It is approximately believed that the magnetic field generated by the two magnetic poles is in the same direction and superimposed in the same direction, and the field intensity is twice as strong as that generated by the magnetic pole part of a single magnet.
Then take the metal processing ground iron dust placed on the plexiglass with a thickness of 10mm, knock the glass to form an even layer covering the glass surface. Put two ndfeb permanent magnets (real picture see fig.7) with N poles fixed on a copper bar below, tap plexiglass to make the iron dust distribution under the action of magnetic field, and get the iron dust distribution under the action of composite magnetic field as shown in figure 6. We can clearly see that the image obtained from the experiment is highly consistent with the magnetic sensing line distribution of the conjecture (figure 4), which strongly proves the correctness of the conjecture proposed above.