Structure and Magnetic Properties of Aerosol Nanoparticles of Fe and Its Alloys

Petrov, Yu. I.; Shafranovsky, E. A.

doi:10.1155/2012/610305

Cited by 6 publications

(7 citation statements)

References 126 publications

(247 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 5 a), the dominant part of each spectrum (component I), of total relative intensity 74–76%, is composed of three or two Zeeman sextets with isomer shift close to zero and HMF values between 32–38 T. This component is attributed to the crystalline Fe-Co phase forming cores of nanochains and possibly containing a trace amount of residues from the manufacturing procedure. The HMF values derived for the sextets decrease with increasing cobalt content, which is in line with the observations reported for bulk [ 37 ] and nano-sized [ 38 ] iron-cobalt alloys as well as the iron-cobalt nanowires [ 39 ]. Spectrum obtained for the sample Fe 0.75 Co 0.25 H 2 also comprises a small (6%) component IV in a form of a set of more smeared sextets corresponding to the HMF values of about 16, 24, and 28 T. They might be attributed to (Fe-Co) 3 C or other Fe-Co-B-C structures [ 40 , 41 ].…”

Section: Resultssupporting

confidence: 90%

“…Undoubtedly, the presence of a shell layer is associated with an initial oxidation of investigated materials, which was confirmed by the performed EDS and TMS measurements. Besides that, this phenomenon has been frequently observed for the nanomaterials composed of iron and/or cobalt, which stay in contact with atmospheric air [ 9 , 19 , 20 , 21 , 25 , 38 , 42 ]. The thickness of initial oxide shells measured for the nanochains investigated in this work is very similar to those already reported in literature [ 9 , 17 , 24 , 26 ].…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Evolution of Structural and Magnetic Properties of Fe-Co Wire-like Nanochains Caused by Annealing Atmosphere

et al. 2021

View full text Add to dashboard Cite

Thermal treatment is a post-synthesis treatment that aims to improve the crystallinity and interrelated physical properties of as-prepared materials. This process may also cause some unwanted changes in materials like their oxidation or contamination. In this work, we present the post-synthesis annealing treatments of the amorphous Fe1−xCox (x = 0.25; 0.50; 0.75) Wire-like nanochains performed at 400 °C in two different atmospheres, i.e., a mixture of 80% nitrogen and 20% hydrogen and argon. These processes caused significantly different changes of structural and magnetic properties of the initially-formed Fe-Co nanostructures. All of them crystallized and their cores were composed of body-centered cubic Fe-Co phase, whereas their oxide shells comprised of a mixture of CoFe2O4 and Fe3O4 phases. However, the annealing carried out in hydrogen-containing atmosphere caused a decomposition of the initial oxide shell layer, whereas a similar process in argon led to its slight thickening. Moreover, it was found that the cores of thermally-treated Fe0.25Co0.75 nanochains contained the hexagonal closest packed (hcp) Co phase and were covered by the nanosheet-like shell layer in the case of annealing performed in argon. Considering the evolution of magnetic properties induced by structural changes, it was observed that the coercivities of annealed Fe-Co nanochains increased in comparison with their non-annealed counterparts. The saturation magnetization (MS) of the Fe0.25Co0.75 nanomaterial annealed in both atmospheres was higher than that for the non-annealed sample. In turn, the MS of the Fe0.75Co0.25 and Fe0.50Co0.50 nanochains annealed in argon were lower than those recorded for non-annealed samples due to their partial oxidation during thermal processing.

show abstract

Section: Resultssupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Evolution of Structural and Magnetic Properties of Fe-Co Wire-like Nanochains Caused by Annealing Atmosphere

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Mössbauer spectroscopy has been performed on the Fe 1– x Co x -NPs at 5 K. FeC-NPs and Fe 0.5 Co 0.5 -NPs have been previously characterized, ,, but the data concerning this composition are included in the present study for comparison purposes. The data fitting reveals different contributions related to a Co-concentration gradient, as the hyperfine field values vary from 33.8 T (Fe) up to 38 T (hyperfine fields reported for Fe–Co alloys). ,, In our case, the 34 T hyperfine field fraction varies from 53% in the case of Fe 0.9 Co 0.1 down to 38% for Fe 0.8 Co 0.2 , 22.5% for Fe 0.7 Co 0.3 , and finally 22% for Fe 0.5 Co 0.5 (see Figure ). The fitting parameters can be found in Table S2.…”

Section: Results and Discussionmentioning

confidence: 51%

“…The data fitting reveals different contributions related to a Co-concentration gradient, as the hyperfine field values vary from 33.8 T (Fe) up to 38 T (hyperfine fields reported for Fe−Co alloys). 14,26,27 In our case, the 34 T hyperfine field fraction varies from 53% in the case of Fe 0.9 Co 0.1 down to 38% for Fe 0.8 Co 0.2 , 22.5% for Fe 0.7 Co 0.3 , and finally 22% for Fe 0.5 Co 0.5 (see Figure 2). The fitting parameters can be found in Table S2.…”

Section: ■ Results and Discussionmentioning

confidence: 53%

Tuning the Composition of FeCo Nanoparticle Heating Agents for Magnetically Induced Catalysis

Marbaix

Mille

Lacroix

et al. 2020

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

Magnetic heating by nanoparticles has recently been successfully employed in heterogeneous catalysis. In such processes, the maximum temperature that can be reached depends on the Curie temperature (T c) of the heating material. Here, in order to extend the range of accessible temperatures and consequently the range of possible reactions, to those requiring high temperatures, we developed and fully characterized a series of FeCo nanoparticles containing different concentrations of cobalt, in order to tune their magnetic properties and Tc. Their efficiency is compared to that of iron carbide nanoparticles, which display a lower Tc. Specific Absorption Rate (SAR) measurements as a function of temperature, performed using a homemade pyrometer-based setup, clearly show that, although the heating power of iron carbide nanoparticles is higher at room temperature, it decreases more rapidly with temperature than that of iron cobalt nanoparticles, in agreement with their lower Tc. In a showcase, Fe 0.5 Co 0.5 nanoparticles allow, in addition to CO 2 hydrogenation, dry reforming of propane and methane, and dehydrogenation of propane, these reactions requiring temperatures of 350°C, 600°C and 700°C respectively. Furthermore, the use of Fe 0.5 Co 0.5 nanoparticles is less energy demanding, as it allows carrying out CO 2 hydrogenation at lower magnetic fields and at frequencies as low as 100 kHz. Dry reforming of methane and propane were carried out in the presence of a Ni nanoparticle-based catalyst whereas dehydrogenation of propane required as a catalyst PtSn nanoparticles synthesized through an organometallic route. Fe 0.5 Co 0.5 nanoparticles can therefore be used as universal heating agents allowing performing reactions up to ca. 700°C upon association with the appropriate catalyst.

show abstract

“…A total of 22 atoms giving 22% content of this phase. The other two sextets are assigned to the Fe 3 Pt phase [46]. The total Fe 3 Pt structure is 61 × (0.03 + 0.03) = 3.66 Fe atoms and 1.22 Pt atoms which gives the content of this phase as 5%.…”

Section: Resultsmentioning

confidence: 99%

Evolution of the Structural and Magnetic Properties of Bulk Fe61Co10B20W1Y8−XPtx Alloys through the Partial Substitution of Pt for Y

Pietrusiewicz

Nabiałek

2020

Materials

View full text Add to dashboard Cite

This paper presents the results of an investigation into rapidly quenched Fe-based alloys with the chemical formula: Fe61Co10B20W1Y8−xPtx (where x = 3, 4, 5). In these alloys, a small quantity of Pt was added, and the Y content was reduced concurrently. Samples of the aforementioned alloys were injection-cast in the form of plates with the dimensions: 0.5 mm × 10 mm × 10 mm. The resulting structure was examined using X-ray diffractometry (XRD), Mössbauer spectroscopy and scanning electron microscopy (SEM). The results of the structural research reveal that, with a small addition of Pt, areas rich in Pt and Y are created—in which Fe-Pt and Pt-Y compounds, with different crystallographic systems, are formed. It has also been shown that an increase in Pt content, at the expense of Y, contributed to the formation of fewer crystalline phases, i.e., it allowed a material with a more homogeneous structure to be obtained. Magnetic properties of the Fe61Co10B20W1Y8−xPtx (where x = 3, 4, 5) alloy samples were tested using a vibrating sample magnetometer (VSM). The magnetic properties of the investigated materials revealed that the saturation magnetisation increased with increasing Pt content, at the expense of Y. This effect is due to the occurrence of different proportions of crystalline magnetic phases within the volume of each alloy.

show abstract

Structure and Magnetic Properties of Aerosol Nanoparticles of Fe and Its Alloys

Cited by 6 publications

References 126 publications

Evolution of Structural and Magnetic Properties of Fe-Co Wire-like Nanochains Caused by Annealing Atmosphere

Evolution of Structural and Magnetic Properties of Fe-Co Wire-like Nanochains Caused by Annealing Atmosphere

Tuning the Composition of FeCo Nanoparticle Heating Agents for Magnetically Induced Catalysis

Evolution of the Structural and Magnetic Properties of Bulk Fe61Co10B20W1Y8−XPtx Alloys through the Partial Substitution of Pt for Y

Contact Info

Product

Resources

About