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Ferrite is a non-metallic magnetic material, also called iron oxide. It is composed of ferric oxide and one or more other metal oxides (for example: nickel oxide, zinc oxide, manganese oxide, magnesium oxide, oxide Barium, strontium oxide, etc.) is prepared and sintered. Its relative permeability can be as high as several thousand, and its resistivity is 1011 times that of metal. The eddy current loss is small. It is suitable for making high-frequency electromagnetic devices. Ferrite has hard magnetic, soft There are five types of magnetism, moment magnetism, gyromagnetism and piezomagnetism.

Soft magnetic materials, such materials are easy to magnetize and demagnetize under a weak magnetic field, such as zinc-chromium ferrite and nickel-zinc ferrite. Soft magnetic ferrite is currently widely used, with many varieties, large quantities, and production value A kind of high ferrite material. It is mainly used as a variety of inductive components, such as filter cores, transformer cores, wireless electromagnetic cores, and tape recording and video heads. It is also a key material for magnetic recording components.

Permanent magnet ferrite is a kind of compound with uniaxial anisotropy hexagonal structure. It is mainly barium, strontium, lead three ferrites and their composite solid solutions. There are homosexual magnetism and heterogeneous magnetism. Because of this type of iron After the external magnetization field disappears, the ferrite material can still retain a strong and constant remanence for a long time, and can be used to generate a constant and stable magnetic field in the external space. It has a wide range of applications, such as: in all kinds of electric meters, power generation Used as permanent magnets in phones, telephones, speakers, televisions and microwave devices.

Ferrite hard magnetic materials are not easy to demagnetize after magnetization. Therefore, they are also called permanent magnetic materials or constant magnetic materials. Such as barium ferrite, iron and steel ferrite, etc. It is mainly used for recorders, pickups, speakers in telecommunication devices, Magnetic cores of various instruments, etc.