A rare earth permanent magnetic alloy based on Sm2Fe17 N2.3 intermetallic compound.
In 1990, J. M. D.Coey et al. from Ireland found that Sm2Fe17 irreversibly absorbed a large amount of nitrogen through gas-solid reaction above 300℃. When nitrogen atoms enter Sm2Fe17, a new interstitial compound, Sm2Fe17 N2.3, is generated, which not only increases the monocyte volume of Sm2Fe17 (about 3%), but also significantly increases the Curie temperature (Tc = 476℃). Moreover, at room temperature there is a high saturation magnetization (Ms = 1.54T) and a large anisotropic field, HA = 14T. These are the important characteristics that make Sm2Fe17 N2.3 an excellent permanent magnet material, so Sm2Fe17 N2.3 attracts people's attention.
High performance samarium ferrite magnetic powder has been developed in laboratory. The magnetism reached Br = 1.3t, HCJ=828kA/m, (BH) Max = 238.8kj /m3. The maximum coerce force of magnetic powder is HCJ=2874kA/m, and this magnetic powder can be used to make a binding magnet with high Curie temperature.
In 1991, Asahi Corporation of Japan announced that it had developed high-performance anisotropic samarium ferronitrogen magnetic powder and binding magnet, and the magnetic energy product of its magnetic powder compacted body reached (BH) Max =167.2kJ/m3, and the magnetic energy product of the binding magnet was also close to 160kJ/m3. Because this is a new iron-based rare earth compound with a higher Curie temperature, it is called the fourth-generation rare earth permanent magnetic alloy.