What is SmCo magnet?
Besides the NdFeB magnets, the SmCo magnet is another type of Rare-earth magnet mainly composed of Samarium-Cobalt alloys. A SmCo magnet may have a magnetic strength comparable to that of a NdFeB one, but is higher in temperature rating and coercivity.
What are the Characteristics of SmCo magnets?
Samarium Cobalt (SmCo) permanent magnets are known for their high magnetic strength, exceptional temperature stability, and reliable performance. As a result, they rarely require a coating to combat corrosion and therefore are more suitable for certain applications than Neodymium.
Attributes of Samarium Cobalt:
• High resistance to demagnetization
• High energy (magnetic strength is strong for its size)
• Good temperature stability
• Pricing for samarium cobalt is market-sensitive
SmCo magnets are often used when a wide range of operating temperatures is expected or if temperature effects must be mitigated, as when high accuracy or highly stable performance is desired. A potential challenge is their propensity to chip and crack, due to their brittle nature.
What are the applications of SmCo magnets?
Samarium cobalt magnets are often used in high-performance permanent magnet motors, medical instruments, magnetic couplings, magnetic bearings, gyroscopes, accelerometers, voice coil motors, particle accelerators, sputtering deposition, Halbach arrays, magnetic separation devices, speakers, microphones, undulators, wigglers, particle beam focusing devices, and many others.
What are the SmCo Magnets’ Composition, Series and Types?
SmCo magnets are available in two series defined by the ratio of Samarium to Cobalt: Series1-5 (SmCo5) and Series 2-17 (Sm2Co17).
These magnets are composed of Samarium-Cobalt alloys with Sm-Co ratio of 1-5, that is to say, one atom of Samarium with five atoms of Cobalt. By weight the Samarium would occupy 36% of the total. By weight, this samarium cobalt magnet alloy will typically contain 36% Samarium with the balance Cobalt. This series of SmCo magnet is able to provide Max. Energy Product of 25 MGOe and has a reversible temperature coefficient of -0.05%/°C. In addition, this series is easier to calibrate to a specific magnetic field than the Sm2Co17 series.
This series is composed of Samarium-Cobalt alloys with SmCo ratio of 2 to 17, that is to say, 2 Samarium atoms with 17 Cobalt atoms. It also contains other elements such as iron, copper, Zirconium, Hafnium but in very small quantities. By weight, the Samarium occupies about 25% of the total.
Currently, in the magnet market, two types of SmCo magnets are available: the bonded type and the sintered type.
Bonded SmCo magnets
The bonded SmCo magnets are anisotropic ones manufactured with magnet powder held in place by epoxy resins or other special “binders”. Energy products of the bonded magnet range from 5 MGOe to 15.1 MGOe.
Sintered SmCo magnets
Sintered SmCo magnets are generally manufactured through this process: alloy milling to fine powder-powder pressed-magnetic fields applying-sintering in special furnace-grounding and shaping-coating.