Magnetic properties of carbon-encapsulated Fe–Co alloy nanoparticles

Abstract

Carbon-encapsulated Fe-Co alloy nanoparticles (Fe-Co(C)) have been fabricated with different Co/Fe ratios by an efficient solid-state route using melamine as carbon source. The structure and morphology of Fe-Co(C) nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The XRD characterization results reveal that all products are alloys with no carbide impurity. The TEM and HRTEM observations show that the alloy nanoparticles are encapsulated in carbon shells. Additionally, the reactions involved in the syntheses are postulated. The variation of magnetic properties of Fe-Co(C) with Co/Fe has been discussed according to the room temperature VSM measurement results.

Graphitization of Miscanthus grass biocarbon enhanced by in situ generated FeCo nanoparticles

“…29 It can be seen in the samples that were treated with iron that Fe 3 C was formed, based on the peaks around the (110) peak, at 2θ = 42.9°, 43.7°, and 45.9°, as expected based on the findings of Thompson et al 13 The formation of this may be a result of iron reacting with gasses being formed during pyrolysis including CH 4 49 or potentially through an intermediate Fe 3 N phase. 50 The XRD pattern of the samples treated with iron and cobalt gives evidence of a Co/Fe alloy forming with face centered cubic (fcc) 51 or body centered cubic (bcc), 52 according to the (110), (200), and (211) peaks at 2θ = 45.0°, 65.5°and 83.0°respectively. 53 Though the (110) peak can also be related to zerovalent iron, in this case the existence of the (200) and (211) peaks suggests that in this sample it may be due to a Co/Fe alloy as well.…”

“…6(C and D) it appears that even along the edge of the carbon phases, the alloy nanoparticles are surrounded by carbon layers, described as a "core-shell structure". 52 This may be due to the nanoparticles providing a site for carbon to begin stacking, eventually promoting the outward growth of graphite layers. 57 The confirmation of the presence of FeCo nanoparticles not only allows for understanding the catalytic pyrolysis mechanism, but proceeds to open new routes to the development of multifunctional materials.…”

Structural Analysis and Magnetic Properties of FeCo Alloys Obtained by Mechanical Alloying

“…Due to the interesting effect of the mechanical alloying in their magnetic and mechanical properties, the interest in the FeCo alloy synthesized by this method has been increased during the last years, especially when this alloy is combined with other elements such as Mo [20,21], V [22], Ni [23], Nb [24], and Cr [25] and even when these materials are used to obtain encapsulated carbon [26].…”

Magnetic Fluid Hyperthermia Based on Magnetic Nanoparticles: Physical Characteristics, Historical Perspective, Clinical Trials, Technological Challenges, and Recent Advances

“…[ 76a ] The challenges with metallic NPs are their poor biocompatibility and chemical stability, high oxidation ability, and pyrophoricity at room temperature. [ 442 ] To address these deficiencies, two or more metallic particles have been merged to form metallic alloy NPs such as Cu–Ni, [ 443 ] Fe–Co, [ 444 ] Ni–Cr, [ 416 ] Fe–Co–Au [ 445 ] and Fe–Cr–Nb–B [ 446 ] in an effort to improve resistance toward oxidation. [ 443,447 ] Cart et al.…”