Any substance can be magnetized more or less in an external magnetic field, but the degree of magnetization is different. According to the characteristics of the material in the external magnetic field, the material can be divided into five categories: paramagnetic material, diamagnetic material, ferromagnetic material, ferrimagnetic material and antiferromagnetic material. Ferromagnetic and ferrimagnetic materials are strong magnetic materials, while diamagnetic and paramagnetic materials are weakly magnetic materials. Generally speaking, magnetic materials generally refer to ferromagnetic materials, which are materials that have a more obvious magnetization reaction in an external magnetic field.
Magnetic materials are classified according to their use, which can be divided into:
Soft magnetic material: A small external magnetic field can be used to achieve greater magnetization, and it is a magnetic material with low coercivity and high permeability. Soft magnetic materials are easy to magnetize and also easy to demagnetize. For example: soft ferrite, amorphous nanocrystalline alloy.
Hard magnetic materials: also called permanent magnetic materials, which refer to materials that are difficult to demagnetize once magnetized. Its main feature is high coercivity, including rare earth permanent magnetic materials, metal permanent magnetic materials and permanent magnet ferrites.
Functional magnetic materials: mainly magnetostrictive materials, magnetic recording materials, magnetoresistance materials, magnetic bubble materials, magneto-optical materials and magnetic thin film materials, etc.
Uses of hard magnetic materials:
The main applications based on the principle of electromagnetic force are: speakers, microphones, meters, buttons, motors, relays, sensors, switches, etc.
Applications based on the principle of magnetoelectric action mainly include: magnetrons and traveling wave tubes and other microwave tubes, picture tubes, titanium pumps, microwave ferrite devices, magnetoresistive devices, Hall devices, etc.
Applications based on the principle of magnetic force mainly include: magnetic bearings, concentrators, magnetic separators, magnetic chucks, magnetic seals, magnetic blackboards, toys, signs, password locks, photocopiers, thermometers, etc. Other applications include: magnetic therapy, magnetized water, magnetic anesthesia, etc.
Application of soft magnetic materials:
Mainly used for magnetic antennas, inductors, transformers, magnetic heads, earphones, relays, vibrators, TV deflection yokes, cables, delay lines, sensors, microwave absorbing materials, electromagnets, accelerators, high-frequency acceleration cavities, magnetic field probes, magnetic substrates , Magnetic field shielding, high frequency quenching energy accumulation, electromagnetic chuck, magnetic sensitive components, etc.
