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德语Low Temperature Coefficient Samarium Cobalt Magnet (SmCo) is an extremely reliable rare-earth magnet used in mission critical applications. The SmCo magnet offers excellent performance over a broad temperature range and less variation in output with changing temperatures than NdFeB magnets, making it the optimal choice for extreme temperature environments such as cryogenic or high-temperature environments.
SmCo magnets come in various shapes, sizes and strengths - perfect for aerospace, automotive, sensor, loudspeaker and motor applications. SmCo magnets may also be coated with advanced coatings for improved vacuum and medical applications or to facilitate soldering onto printed circuit boards.
SmCo magnets tend to be anisotropic, or having one direction of magnetization preference - due to how material is sintered during production - which may present problems when used in systems where magnets must work in multiple orientations simultaneously. However, this issue can usually be overcome simply by making sure that the magnet is oriented correctly.
Conventional SmCo magnets generally feature an energy product of 15-24 mega gauss-oersteds (MGOe). Series 1-5 magnets contain one samarium atom for every five cobalt atoms; these have now been eclipsed by more advanced series 2-17 magnets with MGOe ratings from 22 to 32.
Samarium cobalt magnets are typically manufactured through calcium co-reduction of mixtures containing Gd, Sm and Er with cobalt powder. Essen Magnetics offers two alloys produced using this process - SmCo1-5 and Sm2Co17 - which use this process.
Once raw materials have been reduced to fine powder form, they are sintered in a magnetic field using a mixture of iron, cobalt and hafnium to produce dense, brittle and strong sintered magnet material. Once this step is complete, machined products are produced at any desired dimensions using wet diamond cutting and grinding tools in conjunction with sufficient water-based coolant - otherwise samarium cobalt can spontaneously ignite under certain circumstances and must therefore be treated differently than other rare earth magnets.
SmCo magnets require little maintenance and have long lifespans in most applications, though its Curie temperature can be relatively low. Due to its temperature stability, however, SmCo makes an ideal material for sensitive applications like travelling wave tubes and gyroscopes. Many research hotspots are currently investigating ways of further increasing its temperature coefficient of remanence (aBr), giving SmCo an edge over commercially available rare-earth magnets like NdFeB or sintered ferrite magnets so it could operate under extremely low temperature environments without losing performance.
Low temperature coefficient magnet
