It is determined by the characteristics of the magnet. If it is interpreted according to the atomic current, it is the magnetic field generated by the current to magnetize other objects. The magnetized objects generate electric fields and electric fields. It is made up of nuclei and electrons. Inside the atom, electrons are constantly spinning and revolving around the nucleus. Both of these movements of electrons create magnetism. But in most matter, the electrons move in different directions and chaotic, and the magnetic effects cancel each other out. Therefore, most substances are not magnetic under normal circumstances. Ferromagnetic substances such as iron, cobalt, nickel or ferrite are different. The electron spins in it can be spontaneously arranged in a small range to form a spontaneous magnetization region, which is called a magnetic domain. After the ferromagnetic substance is magnetized, the internal magnetic domains are arranged neatly and in the same direction, which strengthens the magnetism and constitutes a magnet. The process of attracting iron of a magnet is the magnetization process of the iron block. The magnetized iron block and the magnet of different polarities have an attractive force, and the iron block is firmly "sticked" to the magnet.

Natural magnets are iron tetroxide and man-made magnets are usually steel. After the steel is magnetized, it will always retain its magnetic properties. The natural permanent magnets generally referred to are not only ferrite (iron tetroxide), but also various permanent magnet materials such as iron-cobalt-nickel alloys and rare earth alloys of iron, such as aluminum-nickel alloys. Cobalt, samarium cobalt, neodymium iron boron, these are also very common, and the magnetism is very strong. These substances can be magnetized by the constant magnetic field of the magnetic field, and they are magnetic and do not disappear after magnetization. The composition of artificial magnets is determined according to the magnetization properties of various metals. The magnet is close to (touches) the magnetic material, and the material is induced to form a synonymous pole at one end, and the same name pole is formed at the other end.

Magnet classification

A. Temporary (soft) magnets

a. Meaning: The magnetism is short-lived and disappears when the magnet is removed

b. Example: iron nails, wrought iron

B. Permanent (hard) magnet

a. Significance: After magnetization, it can retain magnetism for a long time.

b、Example: steel nails

Based on the above information, the summary is as follows:

According to the principle of electromagnetic induction, a strong current can generate a strong magnetic field, and use the strong magnetic field to magnetize ferromagnetic substances, and because the magnetization characteristics of different substances are different, some substances are easy to magnetize, and not easy to lose magnetization (loss of magnetization). Magnetism), can retain the magnetism for a long time. Magnetizing this material creates a magnet.

Use a magnetizer to magnetize hard magnets. According to the principle of electromagnetic induction, the electric current can generate a magnetic field, and use the strong magnetic field to magnetize the hard magnetic material

Magnetic materials commonly called magnets are actually several different things: The most common magnets, such as those used in ordinary speakers, are ferrite magnets. They are iron scales (flaky iron oxides) that fall off the surface of the steel billet during the hot rolling process of the iron and steel plant. , and then sintered in a reducing electric furnace (passing hydrogen) to reduce part of the oxide to ferrite, cool it, and then put it into an exciter to magnetize it. Higher-grade than them are magnetic steels: magnetic steels are real steels, composed mainly of high nickel content in addition to iron. It is generally smelted in an intermediate frequency electric furnace (only 100 kilograms per furnace), and cast and formed. Because some planes have precision requirements, they are generally ground with a grinder. Then it is magnetized to become a product. This kind of magnet is used in all kinds of electric meters that measure electricity. The more advanced magnetic materials are NdFeB magnetic materials. They are substances containing the rare earth elements neodymium, iron and boron. It is produced by the method of cemented carbide: after powdering - mixing - molding - sintering - finishing - magnetization. This type of magnetic material has the highest magnetic field strength, the best performance and the most expensive price. It is only used in national defense industry and precision equipment. The rotor of the stepper motor in the electronic watch is that. Ah, this magnetic material must be used in maglev trains.

The ferrite permanent magnet materials include: strontium-ferrite permanent magnet material and barium-ferrite permanent magnet material, which are divided into isotropy and anisotropy, speaker magnets generally use ferrite Permanent magnet materials; metal permanent magnet materials mainly include AlNiCo permanent magnet materials and rare earth permanent magnet materials. Rare earth permanent magnet materials are divided into: samarium cobalt permanent magnet materials and neodymium iron boron permanent magnet materials. Rare earth permanent magnet materials are made by powder metallurgy process.