Basic knowledge of magnetic materials

There are many types of magnets, which are generally divided into two categories: permanent magnets and soft magnets. What we call magnets generally refers to permanent magnets.
Permanent magnets are divided into two categories:
The first category is: metal alloy magnets including NdFeB magnets (Nd2Fe14B), Samarium Cobalt magnets (SmCo), Alnico Magnets (ALNiCO)

The second category is: ferrite Permanent Magnet materials (Ferrite)

1. Ndfeb Magnet: It is the magnet with the highest commercial performance found at present. It is called the magnet king. It has extremely high magnetic performance and its maximum magnetic energy product (BHmax) is more than 10 times higher than that of ferrite. Its own machining performance is also quite good. Operating temperature up to 200 degrees Celsius. Moreover, its texture is hard, its performance is stable, and it has a good price/performance ratio, so it is widely used. However, because of its strong chemical activity, it must be treated with a surface coating. (such as Zn, Ni, electrophoresis, passivation, etc.).

2. Ferrite Magnet: its main raw materials include BaFe12O19 and SrFe12O19. Manufactured by the ceramic process method, the texture is relatively hard, and it is a brittle material. Because of its good temperature resistance, low price and moderate performance, Ferrite Magnets have become the most widely used permanent magnets.

3. AlNiCo magnet: It is an alloy composed of aluminum, nickel, cobalt, iron and other trace metal elements. The casting process can be processed into different sizes and shapes, and the machinability is very good. Cast AlNiCo permanent magnets have the lowest reversible temperature coefficient, and the working temperature can be as high as 600 degrees Celsius. AlNiCo permanent magnet products are widely used in various instrumentation and other application fields.

4. Samarium cobalt (SmCo): According to the different components, it is divided into SmCo5 and Sm2Co17. Its development is limited due to the high price of its materials. As a rare earth permanent magnet, samarium cobalt (SmCo) not only has a high magnetic energy product (14-28MGOe), reliable coercivity and good temperature characteristics. Compared with NdFeB magnets, samarium cobalt magnets are more suitable for working in high temperature environments.
The following are the precautions for the use of magnets, please be sure to read them before using our company's magnet products.
1. During the use of the magnet, ensure that the workplace is clean, so as to prevent iron filings and other small impurities from being adsorbed on the surface of the magnet and affecting the normal use of the product.
2. NdFeB magnets are suitable to be stored in a ventilated and dry room. Acidic, alkaline, organic solvents, water, high temperature and humid environments can easily cause the magnets to corrode, the coating layer falls off, and the magnets are powdered and demagnetized. More attention should be paid to unplated products, which can be properly oiled to prevent rust during storage, which is the main reason why we recommend anti-corrosion treatment on the surface of NdFeB magnets.
3. Store magnets away from magnetic disks, magnetic cards, magnetic tapes, computer monitors, watches and other objects sensitive to magnetic fields, as well as electronic medical devices such as heart pacemakers, otherwise it is very dangerous.
4. The material of the magnet is hard and brittle. During transportation and installation, it should be ensured that the magnet will not be severely impacted. If the method is improper, it will easily cause the magnet to be damaged and cracked.
5. The magnet should be shielded when transported in the magnetized state, especially the air transport must be completely shielded.
6. When operating and assembling, be careful to extract one by one to avoid collision and damage, and prevent the scattered fragments generated by the magnet attracting and impacting from entering the eyes and causing harm to the human body.
7. Because NdFeB magnets are very strong, you should avoid hands or other parts of your body being clamped by the magnets during operation. For larger magnets, you should pay more attention to personal safety and protection.
8. Magnets with strong magnetism (neodymium iron boron and samarium cobalt) should not be placed together with magnets with weak magnetism (aluminum nickel cobalt and ferrite).
9. Please do not put the magnet where the child can reach, so as not to accidentally eat it.