Types of Permanent Magnet Materials
Magnetism is one of the basic properties of matter. Magnetic phenomena are associated with various forms of electric charge motion. As the move and spin of electrons in any substances more or less can produce magnetic field, all substances are magnetic, which can be divided into paramagnetic material, diamagnetic material, ferromagnetic material, antiferromagnetic material and ferrimagnetic material according to the different nature of magnetism. Among them, ferromagnetic material and ferrimagnetic material belong to strong magnetic material, which are generally referred to as magnetic material.
Classification, properties and applications of magnetic materials:
1. Ferrite magnetic material:generally refers to the conforming oxides of iron oxide and other metal oxides. Most of them have ferrimagnetism. Characteristic: The resistivity is much higher than that of metal, about 1-10 (to the 12th power) Euro/cm, so the eddy loss and skin effect are small and it is suitable for high frequency use. The saturation magnetization is low, so it is not suitable for high magnetic density. Curie temperature is relatively low.
2. Ferromagnetic material: refers to the material with ferromagnetism. For example, iron, nickel, cobalt and their alloys, and alloys of some rare earth elements. Under Curie temperature, it can be magnetized to high magnetic intensity in magnetic field.
3. Ferrimagnetic materials: refers to materials with ferrimagnetic properties, such as various ferrites, which can be magnetized to high magnetic intensity in magnetic field.
4. Permanent magnet material:The magnet can hold strong magnetism after being magnetized and being moved out of magnetic field. It is characterized by high coercivity and large magnetic energy product. It can be divided into a) aluminum-nickel-cobalt, rare-earth-cobalt, neodymium-iron-boron, etc.; b) ferrite permanent magnet, e.g., barium ferrite, strontium ferrite; c) other permanent magnets, such as plastic magnet, etc.
5. Soft magnetic materials: materials that are easy to magnetize and demagnetize. The working frequency of Mn-Zn ferrite soft magnetic material is between 1K and 10M. While that of Nickel-zinc ferrite soft magnetic material is generally 1-300 MHZ.
6. Metal soft magnetic material: Compared with ferrite, it has high saturation magnetic induction strength and low coercivity, such as engineering pure iron, iron-aluminum alloy, iron-cobalt alloy, iron-nickel alloy, etc. It is often used in transformers.