Ferromagnetic materials such as iron, cobalt, nickel or ferrite are different. The internal electronic spins can be spontaneously arranged in a small range to form a Spontaneous magnetization region, which is called a magnetic domain. After magnetization of ferromagnetic materials, the internal magnetic domains are arranged neatly and in a consistent direction, strengthening the magnetism and forming a magnet. The process of attracting iron by a magnet is the magnetization process of the iron block. The magnetized iron block and the magnet generate attraction between different polarities, and the iron block firmly "sticks" to the magnet.

Natural magnets are made of iron trioxide, while artificial magnets are usually made of steel. After being magnetized, steel will always retain its magnetism. Generally, natural permanent magnets are not only ferrite (ferric oxide), but also various permanent magnet materials such as iron cobalt nickel alloys and rare earth alloys of iron, such as aluminum nickel cobalt, samarium cobalt, neodymium iron boron. These materials are also very common and have strong magnetism. They can be magnetized by a constant magnetic field, and after magnetization, they themselves have magnetism and do not disappear.

The composition of artificial magnets is determined according to the magnetization properties of various metals as needed A magnet approaches (touches) a magnetic substance, which induces a synonymous pole at one end and generates a homonymous pole at the other end. Classification of Magnets A. Temporary (Soft) Magnets a. Meaning: Magnetism is temporary and disappears when the magnet is moved away. b. Example: Iron nails, wrought iron B. Permanent (hard) magnets a. Meaning: After magnetization, it can maintain magnetism for a long time. b. Example: Steel nails can be summarized as follows based on the above information: According to the principle of electromagnetic induction, a strong current can generate a strong magnetic field. By using a strong magnetic field to magnetize ferromagnetic materials, and due to the different magnetization characteristics of different substances, some substances are easy to magnetize and are not easy to lose magnetism (demagnetize), which can maintain magnetism for a long time. Magnetizing this material produces a magnet. Use a magnetizer to magnetize hard magnets.

According to the principle of electromagnetic induction, electric current can generate a magnetic field, and using a strong magnetic field to magnetize hard magnetic materials is commonly referred to as a magnetic material of a magnet. In fact, there are several different things: ordinary magnets, such as those used in general loudspeakers, are ferromagnetic materials. They are produced by using iron scales (iron oxides in the form of flakes) that fall off the surface of steel billets during the hot rolling process of steel mills. After impurity removal, crushing, and adding a small amount of other substances, they are pressurized and formed in a steel mold. Then, they are sintered in a reducing electric furnace (through hydrogen) to reduce some of the oxides to ferrite, cooled, and magnetized in an exciter. What is better than them is magnetic steel: magnetic steel is a true steel, consisting mainly of a high content of nickel in addition to iron. It is generally melted in a medium frequency electric furnace (each furnace weighs only a hundred or ten kilograms) and cast into shape. Due to the accuracy requirements of certain surfaces, it is generally ground and processed using a grinder. Then magnetize and become a product. This type of magnetic steel is used in various types of electricity meters for measuring electricity. A better magnetic material is neodymium iron boron magnetic material. They are substances containing rare earth elements neodymium, iron, and boron. The production is made by the method of hard alloy: through powder making, mixing, molding, sintering, precision processing, and magnetization. This type of magnetic material has high magnetic field strength, good performance, and is relatively expensive. It is only used in national defense, military industry, and precision equipment. The rotor of the stepping motor in the electronic watch is. Ah, the Maglev must use this kind of magnetic material. Ferrite permanent magnet materials include strontium ferrite permanent magnet materials and barium ferrite permanent magnet materials, which can be divided into isotropy and anisotropy. Ferrite permanent magnet materials are commonly used in speaker magnets; Metal permanent magnet materials mainly include aluminum nickel cobalt permanent magnet materials and rare earth permanent magnet materials. Rare earth permanent magnet materials can be divided into samarium cobalt permanent magnet materials and neodymium iron boron permanent magnet materials. Rare earth permanent magnet materials are made through powder metallurgy processes.