List of Magnets That Can Withstand High Temperatures
The normal working temperature of the magnet is 80℃. If it passes through high temperature, that is, over the normal working temperature of 80 ℃, demagnetization will occur. Theoretically speaking, the maximum temperature resistance of the magnet is about 230 ℃, and the actual working temperature is also dependent on the actual working temperature.
It is an alloy composed of aluminum, nickel, cobalt, iron and other trace metals. The casting process can be made into different sizes and shapes, with good workability. Casting Al-Ni-Co permanent magnets with high strength magnets have the lowest reversible temperature coefficient and can operate at temperatures up to 600 degrees Celsius. AlNiCo permanent magnet products are widely used in various instruments and other applications.
It is the most commercially available magnet, known as the magnet king, with extremely high magnetic properties. Its BHmax is more than 10 times higher than that of ferrite. The magnetic steel itself has excellent mechanical properties. The working temperature can reach up to 200 degrees Celsius. Powerful magnets are widely used because of their hard texture, stable performance, and good cost performance. But because of its strong chemical activity, the magnet must be treated on its surface. (for example, Zn, Ni, electrophoresis, passivation, etc.) The magnets used in brushless motors usually choose 120 degrees -150 degrees. The neodymium magnet is classified by temperature as M (80-100 ℃), H (100-120 ℃), SH (120-150 ℃), UH (150-180 ℃), EH (180-200 ℃). The magnetic strength of NdFeB magnets is closely related to the change of ambient temperature. Within the working temperature range, the corresponding magnetic force will be weakened when the temperature rises by 1 ℃. After cooling, most of the magnetic force can return to the original level, which is reversible. This is irreversible if the temperature reaches Curie’s and parts of the magnet move violently and demagnetize.
3. SmCo magnet
They are divided into SmCo5 and Sm2Co17 according to their components. Because of the high price of materials, their development is limited. SmCo, as a rare earth permanent magnet, not only has a high magnetic energy product (14-28MGOe), reliable coercivity and good temperature characteristics. Compared with NdFeB magnets, samarium cobalt magnet is more suitable for working in the high-temperature environment.
Its main raw materials include BaFe12O19 and SrFe12O19. Powerful magnets are made by ceramic technology. They are hard and brittle materials. Ferrite magnets have become the most widely used permanent magnets because of their excellent temperature resistance, low cost, and moderate performance.