Explain some characteristics of high temperature magnet in detail
Magnets refer to objects or materials with magnetic fields around and inside them. They are divided into two categories: natural and artificial. Artificial magnets are usually made of metal alloys with strong magnetism. It can also be divided into permanent magnet and non permanent magnet, namely hard magnet and soft magnet. Main composition of natural magnet: Fe3O4, chemical formula Fe3O4, often called magnetic iron oxide. A black crystal with magnetism. It can be regarded as a compound composed of ferrous oxide and iron oxide. Because there are two different valence ions in the crystal of Fe3O4, one third of which is Fe2 +, two thirds is Fe3 +, which is a complex compound. It does not dissolve in water and does not react with water. It reacts with acid and is insoluble in alkali. It is mainly used for making primer and topcoat, magnetic materials in electronic industry and antirust agent in construction industry. The magnetic force is arranged in the order of NdFeB magnet, SmCo magnet, alnico magnet and ferrite magnet. There are three main performance parameters to confirm the performance of magnet: remanence br: after the permanent magnet is magnetized to technical saturation and the external magnetic field is removed, the retained BR is called remanent magnetic induction. Coercivity HC: to make the B of permanent magnet magnetized to technology saturation decrease to zero, the required reverse magnetic field strength is called magnetic induction coercivity, referred to as coercivity.