The TR-Fe12 type and the ThMn12 quadratic structure have very interesting intrinsic properties (magnetocrystalline anisotropy HA, saturation magnetization Ms and Curie temperature TC). They are considered as the best alternative to NdFeB magnets, offering TR savings of around 35% by weight.
For Sm-based compounds of the Sm(Fe,Ti,V)12 type, it has been demonstrated that the formation of a phase at grain boundaries by the addition of additive elements can significantly increase coercivity up to 1.4 T. However, remanence remains low, below 1 T, which limits the field of application of these magnets. In this thesis, we propose a study of addition elements likely to increase both the remanence and coercivity of TR-Fe12 type magnets.
For Sm-Fe12 compounds, the additions studied will aim to increase the remanence of these magnets by reducing the rate of Fe substitution by stabilizing elements. They will also promote the formation of paramagnetic phases at grain boundaries to enhance coercivity.