As we all know, samarium cobalt magnets and Neodymium Iron Boron magnets are important rare earth magnets. What are the differences between samarium cobalt magnets and neodymium?
What is Samarium cobalt magnet? What is Neodymium?
Let’s know about them.
Samarium-cobalt magnets consist mainly of samarium and cobalt. Samarium cobalt magnets are also the most expensive of several magnets because of the high price of the two materials themselves.
The magnetic energy product of samarium-cobalt magnet can reach 30MGOe or even higher at present. In addition, samarium cobalt magnets have a high coercivity and high-temperature resistance. They can be used at 350 degrees Celsius, so they can not be replaced in many applications. Samarium cobalt magnet belongs to powder metallurgy products.
Generally, according to the size and shape of the finished product, the manufacturer sinters the block blank and then uses the diamond blade to cut into the finished product size. Because samarium cobalt is conductive, it can be processed by wire cutting. In theory, samarium and cobalt can be cut into shapes that can be cut by wire cutting, without considering magnetization and larger size.
Samarium cobalt magnet, corrosion resistance is good, generally, do not need to carry out anti-corrosion plating or coating. In addition, the texture of the samarium cobalt magnet is very brittle, so it is difficult to process small size or thin-walled products.
Neodymium magnet is a magnet product with wide application and rapid development. Neodymium iron boron has been widely used since its invention, and it has not been more than 20 years.
Because of its high magnetic properties and processability, the price is not very high, so the application field expands rapidly. At present, the magnetic energy product of commercialized NdFeB can reach 50MGOe, which is 10 times that of ferrite.
NdFeB is also a powder metallurgical product, and its processing method is similar to that of SmCo. At present, the highest working temperature of NdFeB is about 180 degrees Celsius. If it is used in harsh environments, it is generally recommended not to exceed 140 degrees Celsius. NdFeB is very susceptible to corrosion. Therefore, most of the finished products need to be electroplated or coated.
Conventional surface treatments include nickel plating, zinc plating, aluminum plating, electrophoresis, etc. If working in a closed environment, phosphating can also be used. Because of the high magnetic properties of NdFeB, NdFeB has been used to replace other magnetic materials on many occasions to reduce the volume of products. If we use ferrite magnets, the size of mobile phones today will not be less than half a brick.
Samarium cobalt magnet and neodymium iron boron magnet have better processing performance. Therefore, the dimension tolerance of the product is much better than that of ferrite. General products, size tolerance can be achieved (+/-) 0.05 mm.
Determining whether or not to use Neo magnets instead of SmCo magnets in your high-performance application is a function of:
When you choose samarium cobalt magnet or neodymium, you need to consider the following aspects of them:
• Magnetic stability required.
• Maximum working temperature.
• Resistance to corrosion.
• size and/or weight limitations.
• Flux requirement for the particular application.
Above all, we need to take magnetic performance into account.
BHmax is the point where a magnet delivers more energy to the minimum volume. If you want to compare the magnetic performance of different types and degrees of permanent magnets, the most convenient method is to consider your BHmax.
NdFeB (N38H): 306 kJ / m3 38 MGO
SmCo (2:17): 208 kJ / m³ 26 MGO
Another parameter that must be taken into account is the flux density at the pole face of a magnet. This value is often confused with the Br, but in fact it is purely the induction in a closed circuit.
NdFeB (N38H): 450 mT (4500 Gauss)
SmCo (2:17): 350 mT (3500 Gauss)
For more information, please visit https://www.stanfordmagnets.com/