As one of the most important components, permanent magnet motors have naturally became the focus of social attention. But how many people know the category of permanent magnet materials? What are the characteristics and pros and cons of different permanent magnet materials? Which type should be selected under different environments and applications? This article is based on the above starting point, to do some characteristic analysis of permanent magnet materials, especially "NdFeB and Samarium Cobalt" rare earth permanent magnets. Rare earth permanent magnets (samarium cobalt, neodymium iron boron) are the most widely used in air compressors, most of which are made by sintering technology. At present, about 1/3rd of rare earth permanent magnet materials are used in the permanent magnet motor market . Rare earth permanent magnets are also known permanent magnet materials with the highest comprehensive performance. It is 8 to 10 times higher than permanent ferrites and 3 to 5 times higher than AlNiCo permanent magnet materials, so they have been widely used. The samarium cobalt permanent magnet is a kind of magnetic material made of samarium, cobalt and other metal rare earth materials through a ratio. It contains SmCo5 and Sm2Co17. Neodymium iron boron (Ne2Fe14B) is a tetragonal crystal composed of neodymium, iron and boron.
Before analyzing the difference in the characteristics of the two major rare earth permanent magnet materials, samarium cobalt (SMCo) and neodymium iron boron (NdFeB), we need to understand the following two definitions:
1)Maximum magnetic energy product: the larger the magnetic energy product, the less magnetic material is needed to produce the same effect. So larger magnetic energy product (BH) is better.
2)Maximum operating temperature: When the temperature is higher than this temperature, the magnetic field drops sharply and it cannot work normally. When the temperature drops to a normal level, part of the magnetism can be restored.
Samarium Cobalt and NdFeB are the two most important series of rare earth permanent magnet materials, each with its own merits.Neodymium iron boron is more excellent in magnetism, but the temperature stability of magnetism is poor, and it is easily affected by temperature. Samarium cobalt has excellent magnetic properties and the best temperature characteristics. Compared with NdFeB, it can adapt to high temperature environments.