Magnetic properties and microstructure of Ti-doped Sm-Fe-N synthesized by reduction diffusion process

Iron-rich intermetallic compound Sm2Fe17N3 is considered to be a highly promising candidate for newgeneration permanent magnetic materials. Here, the Ti-substituted Sm-2(Fe, Ti)(17)N-3 alloys were synthesized using reduction-diffusion and nitridation. The microstructure and magnetic properties of Sm-2(Fe, Ti)(17) and its nitrides, in relation to the effect of Ti substitution, were systematically investigated through a comprehensive experimental approach combined with first-principles calculations. It was revealed that the Ti substitution is very effective in particle refinement of Sm-2(Fe, Ti)(17). The Rietveld analysis of X-ray data demonstrated an expansion in the unit cell volume of Sm-2(Fe, Ti)(17) phase with increasing Ti content. Subsequent nitridation experiments highlighted the beneficial impact of an appropriate Ti addition on the enhancement of both coercivity and remanence in Sm-2(Fe, Ti)(17)N-3 magnetic powder. The highest coercivity of 8.9 kOe was achieved in the sample with a Ti/Fe mole ratio of 0.04. Furthermore, the possible crystallographic occupancy of Ti and its effect on the phase stability are investigated using first-principles calculations. Our results indicated that the phase stability is influenced by the synergistic effect of Ti substitution atoms and interstitial N atoms. The significance of this study lies in its implications for the development of advanced permanent magnetic materials through reductiondiffusion technology.