Nguyen Tien Hiep, Karunakaran Gopalu, Konyukhov Yu V, Minh Nguyen Van, Karpenkov D Yu, Burmistrov I N
Department of Functional Nanosystems and High-Temperature Materials, National University of Science and Technology "MISiS", 119049 Moscow, Russia.
Department of Materials Science and Engineering, Le Quy Don Technical University, Hanoi 100000, Vietnam.
Nanomaterials (Basel). 2021 Jan 29;11(2):341. doi: 10.3390/nano11020341.
This paper presents the synthesis of Fe-Co-Ni nanocomposites by chemical precipitation, followed by a reduction process. It was found that the influence of the chemical composition and reduction temperature greatly alters the phase formation, its structures, particle size distribution, and magnetic properties of Fe-Co-Ni nanocomposites. The initial hydroxides of Fe-Co-Ni combinations were prepared by the co-precipitation method from nitrate precursors and precipitated using alkali. The reduction process was carried out by hydrogen in the temperature range of 300-500 °C under isothermal conditions. The nanocomposites had metallic and intermetallic phases with different lattice parameter values due to the increase in Fe content. In this paper, we showed that the values of the magnetic parameters of nanocomposites can be controlled in the ranges of M = 7.6-192.5 Am/kg, M = 0.4-39.7 Am/kg, M/M = 0.02-0.32, and H = 4.72-60.68 kA/m by regulating the composition and reduction temperature of the Fe-Co-Ni composites. Due to the reduction process, drastic variations in the magnetic features result from the intermetallic and metallic face formation. The variation in magnetic characteristics is guided by the reduction degree, particle size growth, and crystallinity enhancement. Moreover, the reduction of the surface spins fraction of the nanocomposites under their growth induced an increase in the saturation magnetization. This is the first report where the influence of Fe content on the Fe-Co-Ni ternary system phase content and magnetic properties was evaluated. The Fe-Co-Ni ternary nanocomposites obtained by co-precipitation, followed by the hydrogen reduction led to the formation of better magnetic materials for various magnetically coupled device applications.
本文介绍了通过化学沉淀法合成铁钴镍纳米复合材料，随后进行还原过程。研究发现，化学成分和还原温度的影响极大地改变了铁钴镍纳米复合材料的相形成、结构、粒径分布和磁性能。铁钴镍组合的初始氢氧化物通过共沉淀法由硝酸盐前驱体制备，并使用碱进行沉淀。还原过程在300 - 500°C的温度范围内，在等温条件下通过氢气进行。由于铁含量的增加，纳米复合材料具有不同晶格参数值的金属相和金属间相。在本文中，我们表明通过调节铁钴镍复合材料的组成和还原温度，纳米复合材料的磁参数值可以控制在M = 7.6 - 192.5 Am/kg、M = 0.4 - 39.7 Am/kg、M/M = 0.02 - 0.32和H = 4.72 - 60.68 kA/m的范围内。由于还原过程，金属间相和金属面的形成导致磁特性发生剧烈变化。磁特性的变化受还原程度、粒径生长和结晶度增强的影响。此外，纳米复合材料在生长过程中表面自旋分数的降低导致饱和磁化强度增加。这是首次评估铁含量对铁钴镍三元体系相含量和磁性能影响的报告。通过共沉淀法制备，随后进行氢还原得到的铁钴镍三元纳米复合材料，为各种磁耦合器件应用形成了更好的磁性材料。
