Kołodziej Mieszko, Grenèche Jean-Marc, Auguste Sandy, Idzikowski Bogdan, Zubko Maciej, Bessais Lotfi, Śniadecki Zbigniew
Institute of Molecular Physics, Polish Academy of Sciences, Mariana Smoluchowskiego 17, 60-179 Poznań, Poland.
NanoBioMedical Centre, Adam Mickiewicz University, Wszechnicy Piastowskiej 3, 61-614 Poznań, Poland.
Materials (Basel). 2023 Feb 11;16(4):1522. doi: 10.3390/ma16041522.
Iron-based compounds with a ThMn-type structure have the potential to bridge the gap between ferrites and high performance NdFeB magnets. From the point of view of possible applications, the main advantage is their composition, with about 10 wt.% less rare earth elements in comparison with the 2:14:1 phase. On the other hand, the main issue delaying the development of Fe-rich alloys with a ThMn-type structure is their structural stability. Therefore, various synthesis methods and stabilizing elements have been proposed to stabilize the structure. In this work, the influence of increasing Nd substitution on the phase constitution of ZrNdCeFeSi (0 ≤ x ≤ 0.3) alloys was analyzed. X-ray diffraction and Fe Mössbauer spectrometry were used as the main methods to derive the stability range and destabilization routes of the 1:12 structure. For the arc-melted samples, an increase in the lattice parameters of the ThMn-type structure was observed with the simultaneous growth of bcc-(Fe,Si) content with increasing Nd substitution. After isothermal annealing, the ThMn-type structure (and the coexisting bcc-(Fe,Si)) were stable over the whole composition range. While the formation of a 1:12 phase was totally suppressed in the as-cast state for x = 0.3, further heat treatment resulted in the growth of about 45% of the ThMn-type phase. The results confirmed that the stability range of ThMn-type structure in the Nd-containing alloys was well improved by other substitutions and the heat treatment, which in turn, is also needed to homogenize the ThMn-type phase. After further characterization of the magnetic properties and optimization of microstructure, such hard/soft magnetic composites can show their potential by exploiting the exchange spring mechanism.
具有ThMn型结构的铁基化合物有潜力弥合铁氧体与高性能钕铁硼磁体之间的差距。从可能的应用角度来看，其主要优势在于成分，与2:14:1相相比，稀土元素含量约少10 wt.%。另一方面，阻碍具有ThMn型结构的富铁合金发展的主要问题是其结构稳定性。因此，人们提出了各种合成方法和稳定元素来稳定结构。在这项工作中，分析了增加Nd替代量对ZrNdCeFeSi（0 ≤ x ≤ 0.3）合金相组成的影响。X射线衍射和Fe穆斯堡尔光谱法被用作推导1:12结构稳定性范围和失稳途径的主要方法。对于电弧熔炼样品，随着Nd替代量增加，观察到ThMn型结构的晶格参数增大，同时体心立方（Fe,Si）含量增加。等温退火后，ThMn型结构（以及共存的体心立方（Fe,Si））在整个成分范围内都是稳定的。虽然对于x = 0.3，铸态下完全抑制了1:12相的形成，但进一步热处理导致ThMn型相增长约45%。结果证实，通过其他替代和热处理，含Nd合金中ThMn型结构的稳定性范围得到了很好的改善，而这反过来也是使ThMn型相均匀化所需要的。在进一步表征磁性能和优化微观结构之后，这种硬/软磁复合材料可以通过利用交换弹簧机制展现其潜力。
