Abstract Scope |
The great performance of commercial high-energy permanent magnets is strongly dependent on the use of critical and strategic raw materials, such as Dy and Tb, which provide enhanced coercivity and increased thermal stability. To overcome this dependency on scarce materials, worldwide efforts to develop rare-earth lean/free permanent magnets are promoted. ThMn12-type hard magnetic phases are promising candidates due to their high saturation magnetization, Curie point and anisotropy field; these properties are enhanced by the addition of light elements (H, N) at the interstitial sites of the 1:12 crystal structure or by Sm-substitution at the Th site. Progress in the development of coercivity on samples with high anisotropy has been done using different processing methods and the intrinsic properties of the hard-magnetic phases were significantly improved by the proposed techniques. The maximum coercivity reached in these compounds is above 0.6T and 1T in nitride Nd-based and Sm-based 1:12 alloys, respectively. |