Fe-based Ribbons Research Articles

XGBoost algorithm-assisted prediction of amorphous formability of Fe-based nanocrystalline precursor

The completely amorphous structure in the precursor is a significantly important prerequisite for obtaining the perfect amorphous-nanocrystalline duplex structure and the excellent soft magnetic properties of Fe-based nanocrystalline alloy ribbons (FNR). However, the correlation between the amorphous formability (AFA) and the key parameters of FNR precursors is not clear. Herein, a data-preprocessed dataset was established, consisting of 158 FNR samples with amorphous and crystallized precursors. This dataset includes features such as elements, thermal parameters, and calculated parameters. Pearson correlation analysis was performed to assess the linear correlation between any two features, resulting in the removal of eight features. Then the features importance was ranked by random forest (RF) algorithm, and top five key features (e.g., ΔT, VEC1, VEC, P, and B) were retained. A classification predictive model in that the structure of FNR precursors is amorphous or crystalline was constructed based on XGBoost algorithm. The accuracy of the classification model by confusion matrix analysis is up to 97.9 %. Furthermore, SHAP (SHapley Additive exPlanations) results reveal that crystallization temperature intervals (ΔT), valence electron concentration without Fe, Ni, and Co elements (VEC1), as well as valence electron concentration (VEC) play an important role in affecting AFA of FNR precursors. When ΔT > 142 °C, VEC1 > 0.69, and VEC >7.27, the FNR precursors readily obtain a fully amorphous structure. The outstanding classification accuracy and the elucidated correlation between the key features and AFA could guide the discovery of novel fully amorphous FNR precursors.

Effect of ultralow Dy and Gd contents on surface crystallization and domain wall motion of FeCuSiBNbMo alloys

Surface crystallization of Fe-based melt-spun ribbons with high saturation induction leads to the formation of coarse grains after nanocrystallization, which results in a deterioration of the soft magnetic properties. Herein, doping with an ultralow concentration (0.1 at.%) of RE (RE = Dy and Gd) inhibits the surface crystallization of melt-spun FeCuSiBNbMo samples using industrial-grade Nb–Fe raw materials. This inhibition of surface crystallization promotes the formation of uniform and ultrafine nanograins after optimal annealing. Furthermore, the movement of domain wall is significantly affected by the presence of large grains (∼600 nm) in the free surface, which exerts a strong pinning effect on the domain wall motion. This pinning effect can be attributed to the higher magnetic anisotropy energy of the free surface compared to that of the nanocrystal region. The low coercivity observed in the samples with 0.1 at.% Dy and Gd addition is ascribed to the presence of dense and ultrafine nanocrystals, low effective magnetic anisotropy, and a weak pinning effect. This work provides insights into the relationship between surface crystallization, coercivity, domain wall motion, and magnetic anisotropy energy in Fe-based nanocrystalline ribbons.

Interpretation of magnetostrictive sensor data in Mode 1 and Mode 2 of carbon fibre reinforced polymers

Structural health monitoring (SHM) of carbon fibre reinforced polymers (CFRP) provides a valuable way to assess the condition of these materials, which possess desirable traits, but exhibit little elastic failure. Further complications arise due to their multi component nature, which means they can fail in a variety of ways. High-fidelity magnetostrictive SHM technology exhibits higher cost when utilising top-end materials that contain rare-earth elements. At the expense of fidelity, cost can be reduced by using Fe-based ribbons and cheap transducers. This reduction in accuracy can be overcome by coupling a detection array with the development of specific detection schemes for each failure type to reduce signal complexity. In this work, we investigate the failure of CFRP coupons in Mode 1 and 2 failure, using FeSiB ribbons as the actuator either bonded between the CFRP ply or co-cured on the surface. During the measurement, a set of 4 pancake coils are used to measure the change in inductance, as the CFRP fails, thus demonstrating that this magnetostrictive-coil set-up can be used to measure cracks forming and propagating within the CFRP, hence it is a promising SHM system. For the first time, it is demonstrated that there is a correlation between the induction signal and the elastic energy stored within the CFRP coupon.

Role of Cr Element in Highly Dense Passivation of Fe-Based Amorphous Alloy.

The effect of the Cr element on the corrosion behavior of as-spun Fe72-xCrxB19.2Si4.8Nb4 ribbons with x = 0, 7.2, 21.6, and 36 in 3.5% NaCl solution were investigated in this work. The results show that the glass formability of the alloys can be increased as Cr content (cCr) is added up to 21.6 at.%. When cCr reaches 36 at.%, some nanocrystals appear in the as-spun ribbon. With increasing cCr content, the corrosion resistances of as-spun Fe-based ribbons are continually improved as well as their hardness properties; during the polarization test, their passive film shows an increase first and then a decrease, with the highest pitting potential as cCr = 7.2 at.%, which is confirmed by an XPS test. The dense passivation film, composed of Cr2O3 and [CrOx(OH)3-2x, nH2O], can reduce the number of corrosion pits on the sample surface due to chloride corrosion and possibly be deteriorated by the overdosed CrFeB phase. This work can help us to design and prepare the highly corrosion-resistant Fe-based alloys.

Substantial thinning of melt-spun ribbons by an optimised and high-yield ball-milling process

Melt-spun Fe-based ribbons are widely used as the core of transformers and inductors due to their high flux density and low coercivity. However due to their high thickness (∼19 µm) these ribbons are prone to large eddy current losses at MHz frequencies. Despite low yield, ball milling has been widely used to break such ribbons down to thinner flakes to suppress the eddy current losses at high frequency. In this work, we demonstrated an optimized ball milling process with increased yield for flakes in the desired size range (2–4 µm). We have demonstrated that reducing pre milling annealing temperature from 450 to 350 °C increases the yield in desired size range from 2% to 5% and further increasing batch size from 10 to 20 g increases the yield to 21%. The coercivity of the milled flakes increases from 139 to 1352 A/m due to the ball milling process. A post-mill annealing at 350 °C in Ar atmosphere decreases the coercivity to 341 A/m. X-ray diffraction analysis showed no sign of crystallization during ball milling. The result presented here demonstrates an efficient approach to fabricate ultra-thin flakes out of soft magnetic ribbons for high-frequency applications.

Regulation mechanism of giant magneto-impedance effect of multi-field coupling Fe-based alloy

Fe-based amorphous and nanocrystalline alloys are considered as the preferred dual-green energy-saving materials due to their unique magnetic properties, such as high permeability, low coercivity, and near-zero saturation magnetostriction. As such, they have received extensive attention in applications like magnetic core material for high-frequency transformers, common model chokes, ground fault interrupters, and rotors in motors, over the past decades. In this work, Fe<sub>64.8</sub>Co<sub>7.2</sub>Nb<sub>4</sub>Si<sub>4.8</sub>B<sub>19.2</sub> (in atom percent) amorphous alloy ribbons are prepared by using the single roller quenching method, then subsequently subjected to multi-field coupling heating treatment in the air which includes heating by Joule heating effect and tensile stress field. Furthermore, the longitudinally driven giant magneto-impedance effect and magnetic domain structures of ribbons are observed by using 4294A impedance analyzer and magnetic force microscopy, respectively. The magneto-crystalline anisotropy field and stress anisotropy field of ribbons are analyzed by using X-ray diffraction, random anisotropy model, and numerical fitting. Meanwhile, the concept of magnetic anisotropy competing factor (<i>k</i>) is proposed, from the viewpoint of magnetic anisotropy, a mechanism for regulating giant magneto-impedance effect of ribbons prepared with multi-field coupling is studied. It is found that the longitudinally driven giant magneto-impedance effect gradually transforms from the single peak to dome-like with tensile stress increasing. However, a spike and dome-like giant magneto-impedance effect appears during such transformation, which is composed of two parts: spike-like top and dome-like base. Based on the magnetic domain structure of ribbons, it is found that the typical stress-annealed transversal magnetic domain structure is observed in ribbons of <inline-formula><tex-math id="Z-20221115160531">\begin{document}$k \leqslant 0.147$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221376_Z-20221115160531.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221376_Z-20221115160531.png"/></alternatives></inline-formula>, while nucleation and splitting phenomenon of new domains are observed at the transversal magnetic domain wall in ribbons of <i>k</i> > 0.147. Both longitudinally driven giant magneto-impedance effect and domain structures provide evidence to support the competing inhibition effect of magnetic anisotropy which exists in Fe-based alloy ribbon. Therefore, it is suggested that Fe-based alloys exhibit excellent stress-sensitive properties that can be understood by the competing inhibition effects of magnetic anisotropy. It is further shown that the competing inhibition effect of magnetic anisotropy is the main reason for regulating the giant magneto-impedance effect of soft magnetic materials. This multi-field coupling Fe-based alloy has good application prospects in regulating magnetic properties of magnetic materials.

Mechanism of stress induced irreversible magnetic anisotropy in Fe-based alloy ribbons

Fe-based amorphous and nanocrystalline soft magnetic alloys are regarded as the significant dual-green energy-saving materials because of their superior magnetic properties and straightforward fabrication procedure. As such, they have attracted much attention in the fields of the electronic information and electrical power. In this work, Fe<sub>73.5</sub>Cu<sub>1</sub>Nb<sub>3</sub>Si<sub>13.5</sub>B<sub>9</sub> (%) amorphous alloy ribbon is subjected to various physical ageing treatments in nitrogen atmosphere. These treatments include annealing at 540 ℃ for 30 min under different tensile stresses and isothermal tempering without tensile stress for several cycles. The origin of stress-induced magnetic anisotropy is investigated through using dynamic strain analysis, the longitudinally driven giant magento-impedance effect, and synchrotron radiation X-ray diffraction. In the process of tensile stress annealing, it is found that the axial strain of ribbon is elastic strain when annealing temperature is below the glass transition point, and plastic strain when annealing temperature is above the glass transition point; the precipitation of nanocrystalline phase has a pinning effect on amorphous matrix, which slows down the strain rates and makes the tend stable. Additionally, isothermal tempering studies show that the stress-induced magnetic anisotropy and lattice plane anisotropy have different relaxation patterns. It is found through numerical fitting that the stress-induced magnetic anisotropy can reach a stable value of 0.144 by infinite tempering, whereas the lattice plane anisotropy can only relax to zero by finite tempering. A model of nanocrystalline grain distribution anisotropy is developed to re-examine the origin of stress-induced magnetic anisotropy. It supports a viewpoint that the nanocrystalline grain distribution anisotropy <inline-formula><tex-math id="M4">\begin{document}$\Delta \delta $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M4.png"/></alternatives></inline-formula> is responsible for the stress-induced irreversible magnetic anisotropy <inline-formula><tex-math id="M5">\begin{document}${K_{\text{d}}}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M5.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M5.png"/></alternatives></inline-formula>, and that their relationship can be described as a following function: <inline-formula><tex-math id="M6">\begin{document}${K_{\text{d}}} = k\Delta \delta $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M6.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20221509_M6.png"/></alternatives></inline-formula>. Therefore, it is proposed that the stress-induced anisotropy originates from a synergistic interaction between the lattice plane anisotropy and the nanocrystalline grain distribution anisotropy in Fe-based alloy ribbon. This work has important implications for understanding the mechanism of the stress-induced magnetic anisotropy.

Hardness, magnetism and passivation of Fe-Si-B-Nb glasses

Nb is a noble and important element for the Fe based glass manufacture. The mechanical properties, magnetic properties and corrosion behavior of (Fe78Si9B13)100-xNbx (x = 0, 7 and 10) glassy ribbons have been studied by various experimental methods. With the addition of Nb element, the hardness of the Fe-based glasses increases and their coercivity decreases, which is attributed to the ordering tendency of atomic structure by adding Nb atoms. In the potentiodynamic polarization and Mott-Schottky plots, Fe-based glassy ribbons with x = 7 and 10 have a wide passivation platform and an n-type semiconductive surface, while the ribbon with x = 0 does not. By XPS analysis, Nb and B tend to segregate beneath the ribbon surface and form the stable passive film. The Nb addition can improve the hardness, soft magnetism and corrosion resistance of Fe based glasses and will help us to seek for the new type Fe based glasses.

Fe基合金薄带应力感生磁各向异性非线性关系研究

Fe基合金薄带应力感生磁各向异性非线性关系研究

Analysis of Magneto-Optical Hysteresis Loops of Amorphous and Surface-Crystalline Fe-Based Ribbons.

Three Fe-based ribbon-type samples prepared by a conventional planar flow casting process are studied from the viewpoint of the amorphous Fe80Si4B16 and partially surface crystallized Fe80Si10B10, and Fe80.5Nb6.9B12.6, microstructures. Surface magnetic properties are investigated by magneto-optical Kerr microscopy, allowing the measurement of a local hysteresis loop from a selected area on the ribbon surface, and simultaneously, a domain structure corresponding to a definite point at the loop. For an amorphous sample, the changes in the slopes of hysteresis loops are related either to the size of the selected surface area, from which the loop is measured, or to the type, width, and movement of magnetic domains through this area. In the first case, the resizing of the area simulates an effect of changing the diameter of the incident laser beam on the magneto-optical properties of the ribbon. In the latter case, the observed wide-curved and fingerprint domains are responsible for markedly different shapes of the hysteresis loops at lower magnetic fields. If the surface is crystallized, the magnetic properties are more homogenous, showing typical one-jump magnetization reversal with less dependence on the size of the surface area. The magneto-optical experiments are completed by transmission electron microscopy and magnetic force microscopy.

Efficient nanostructured heterogeneous catalysts by electrochemical etching of partially crystallized Fe-based metallic glass ribbons

Although an increasing interest has been attracted to further develop heterostructured catalysts from metallic glasses (MGs) by heat treatment, overcoming surface oxidation effect is still a critical problem for such environmental catalysts. Herein, a short-time electrochemical etching of partially crystallized Fe-based ribbons in 0.3 M H3PO4 electrolyte enables the formation of honeycomb-like nanoporous structure as effective catalytic active sites in Fenton-like process. Studies of structure and surface morphologies reveal that the formation of nanoporous structure by potentiostatic etching originates from electrochemical potential difference of nanocrystals (α-Fe (Si) and Fe2B) and residual amorphous phase in partially crystallized ribbons, where Fe2B having a lower open circuit potential tends to be selectively dissolved. Simultaneously, thin oxide layer after electrochemical etching exposes more active sites for H2O2 activation and provides an effective protection of nanocrystals from massive loss during etching. Investigation of optimal processing conditions suggests that the selection of electrolyte plays an important role; dye degradation rates of etched ribbons in HNO3 and Na2SO4 electrolytes can also achieve at least 2 times higher than that of as-annealed ribbons. This work holds the promise to develop novel environmental catalysts by effective electrochemical etching of partially crystallized ribbons.

Co50Gd48-xFe2Nix amorphous alloys with high adiabatic temperature rise near the hot end of a domestic magnetic refrigerator

In the present work, the Curie temperature (Tc) of the Co50Gd48Fe2 amorphous alloy, which exhibits high adiabatic temperature change (ΔTad) at room temperature, was further improved by small amount of Ni substitution for Gd. The maximum magnetic entropy change (−ΔSmpeak) of the Co50Gd48-xFe2Nix (x = 1 and 2) amorphous ribbons decreases with Ni addition, but is still large than those of the Fe-based metallic glasses. The maximum ΔTad of the Co50Gd48-xFe2Nix glassy alloys near the hot end of a residential refrigerator, which is at least 65% higher than those of the Fe-based glassy ribbons, indicates that the Co50Gd48-xFe2Nix amorphous alloys are the better candidates for the domestic magnetic refrigerants.

Effect of moisturized air on magnetoimpedance response of Fe-based ribbons

High sensitivity and response ratio of magnetoimpedance (MI) sensors have raised interest for using them in different environments for detection of weak magnetic fields of magnetic elements even though the high dependence of the MI response to the surface condition of the MI sensor has limited its application in some environments. In this study, we investigate the effects originating from the MI measurement in moisturized air. Using scanning electron microscopy (SEM) images, it is observed that the surface of an Fe-based MI sensor has become rough and granular after the presence of moisture on its surface. Results can be useful for developing MI sensors for use in different environmental conditions.

Giant Magnetoimpedance Effect Modified by Transverse Shape Anisotropy in Fe-Based Amorphous Ribbon

The magnetoimpedance (MI) effect on the text Fe-based ribbon with different sizes of triangle transverse structures has been investigated. The initial susceptibility ( $\chi _{\mathbf {i}}$ ) and the MI ratio along the width (T-MI) and length (L-MI) directions as a function of the triangle height ( ${h}$ ) were measured and discussed. The text T-MI and $\chi _{\mathbf {i}}$ along the width direction increase with the increase in ${h}$ , while the text L-MI and $\chi _{\mathbf {i}}$ along the length direction decrease with the increase in ${h}$ . These behaviors are mainly attributed to the variation of the effective shape anisotropy ( ${K} _{\mathbf {eff}}$ ) and the corresponding magnetization process, in which ${K} _{\mathbf {eff}}$ mainly originates from the competition of demagnetization effects along the width and length directions. The triangle structures changed the demagnetization fields along the two directions. Thus, the effective shape anisotropy, permeability, and MI were varied. This article also provides an idea to fabricate the MI sensor by introducing transverse shape anisotropy.

ZnO thin layer/Fe-based ribbon/ZnO thin layer sandwich structure: Introduction of a new GMI optimization method

Giant magneto-impedance (GMI) investigations comprising ZnO thin layers have received considerable attention for sensitive sensor applications. Herein, a ZnO thin layer with different thicknesses (92–503 nm) was deposited on surface of Fe-based amorphous ribbon (FeCoSiB) using RF magnetron sputtering. The GMI response and magnetic field sensitivity were investigated. While GMI% increased continuously up to the thickness of 223 nm, further increasing the ZnO thin layer thickness decreased GMI response. The GMI response and magnetic field sensitivity increased from 156% and 1.21%/Oe to 237% and 2.91%/Oe for bare Fe-based ribbon and ZnO thin layer/Fe-based ribbon/ZnO thin layer sandwich structure (223 nm in thickness), respectively. X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize ZnO-enhanced structural parameters. A vibrating sample magnetometer (VSM) was used to indicate the role of the ZnO thin layer in the GMI response. Similar increasing and decreasing trends of GMI% as a function of thickness were observed in transverse permeability of samples as determined by VSM. Our results provide a simple approach to achieve high GMI response and magnetic field sensitivity by using a dielectric sandwich structure.

High-temperature magnetocaloric effect in devitrified Fe/Co based glassy monolayer and bilayer ribbons

Rapidly quenched Co- and Fe-based monolayer and their bilayer prepared through double nozzle technique have been characterized to investigate its microstructural and magnetic properties and their possibility as high-temperature magnetocaloric material. The Co- and Fe-based monolayer ribbons displayed Curie temperatures (TC) of 463 K and 700 K, respectively. Magnetic entropy change ∆SM of the bilayer was measured at a low magnetizing field of 1 T in the temperature spans covering separately for TC of Co- and Fe-based ribbons corresponding to separate entropy at low- and high-temperature regime. The ∆SM value at TC of Fe-based ribbon displayed values in the span of 1.13–1.71 J kg−1 K−1 in their monolayer and bilayer state. On incipient nanocrystallisation at 773 K, the ∆SM and refrigerant capacity (RC) around TC of cobalt-based bilayer ribbon revealed comparable values as in their as-quenched state. However, nanocrystallisation elevated the ∆SM of bilayer across TC of the Fe-based regime to a high value close to 4.6 J kg−1 K−1 with a fairly elevated RC of 96 J kg−1. The enhanced ∆SM associated with the formation of Fe-based nanocrystallites is evidenced through transmission electron microscopy. The interdiffusion of ferromagnetic elements Fe and Co is also supposed to elevate the ∆SM as well as the RC of the glassy system in the bilayer ribbons.

The characteristics of multiple isothermal tempered Fe-based alloy ribbons

The magnetic properties of Fe-based alloy ribbons are sensitive to stress, and it’s an interesting scientific question whether stress-induced magnetic anisotropy during annealing procedure can be eliminated by tempering. In this paper, the synchrotron radiation technique was used to observe the microstructure of Fe<sub>73.5</sub>Cu1Nb<sub>3</sub>Si<sub>13.5</sub>B<sub>9</sub> amorphous ribbons annealed at 540 ℃ for 30 minutes under 394.7MPa stress and tempered several times at the same temperature. The macroscopic elongation of the samples during stress annealing and tempering was recorded by SupereyesB011 microcamera, and the magnetic anisotropy of the samples was measured by HP4294A impedance analyzer. After fitting the experimental data, it is found that: (a) The lattice anisotropy, macroscopic strain and magnetic anisotropy of the sample show negative exponential attenuation with the tempering times, and their final residual are 19.04%. 98.27% and 31.65%. (b) Multiple tempering can not completely eliminate lattice anisotropy, macroscopic strain and magnetic anisotropy induced by stress annealing. (c) The magnetic anisotropy of the sample has a linear relationship with the lattice anisotropy, but the intercept between the reverse extension line of the relation curve and the longitudinal coordinate is not zero. When the lattice anisotropy is zero, there is still 16.36% magnetic anisotropy. This is different from Ohnuma's conclusion that lattice anisotropy is the direct cause of magnetic anisotropy. (d) The structure anisotropy caused by the residual stress after stress annealing is the main cause of magnetic anisotropy, but it is not the only reason. The directional congregation of agglomerated nanocrystalline grains caused by creep of amorphous substrates during stress annealing is also an important cause of magnetic anisotropy induced by stress annealing. Moreover, the magnetic anisotropy induced by the directional congregation of agglomerated nanocrystalline grains due to the creep of amorphous substrates during stress annealing can not be completely eliminated by tempering.

Enhanced magnetoimpedance effect of Fe75.5Cu1Nb3Si13.5B7 ribbon covered by in-situ growth vertical graphene sheets

Vertical graphene-sheets have been successfully in-situ deposited onto Fe75.5Cu1Nb3Si13.5B7 ribbon by plasma enhanced chemical vapor deposition and the enhanced magnetoimpedance effect has been observed in the composites. A mass of curly graphene-sheet clusters can be apperceived if there is no buffer layer during the growth. The 20 nm FeCo film is used as the buffer layer during the deposition, and then vertical growth graphene sheets are covered on the Fe-based ribbon as a film. Compared with the untreated sample, the field-dependent magnetoimpedance effect has been obviously improved with graphene covered at low frequencies. At a certain frequency, the magnetoimpedance effect of one side graphene covered sample shows enlargement, but the both sides covered sample shows the reversed tendency. We mainly attribute the reason to the enhanced transverse permeability induced by the vertical graphene morphology.

Helium ions irradiation-induced surface damage in Fe-based melt-spun ribbons

The Fe78Si8B14 and Fe78P8B14 ribbons with different wheel speeds were prepared by melt-spinning, and their responses to He+ ion irradiation were investigated. Previous studies had shown that the ion beam resistance capability of amorphous ribbons was better than their corresponding crystalline counterparts. However, no significant changes on the surface at low fluence are observed. At a relatively higher fluence, both the ribbons prepared at low and high wheel speeds behave the similar irradiation responses: peeling, flaking and multi-layer damages occur. The fully amorphous ribbons prepared at a high wheel speed can accommodate partial incident ions owing to the inherent disordered structure. As the irradiation fluence increases, they fail to accommodate the excess incident ions, which easily aggregate to result in the surface damage. While the partial amorphous ribbons prepared at a low wheel speed possess lots of unstable crystalline grain boundaries owing to the precipitation of Si- or P-rich phase, which may act as the source for the irradiation-induced defects annihilation. Results show that the size and the fraction of precipitate phases in amorphous matrix may play a dominated role in resisting the ion irradiation.

Local configurations and atomic intermixing in as-quenched and annealed Fe1−xCrx and Fe1−xMox ribbons

Local atomic configuration, phase composition and atomic intermixing in Fe-rich Fe1−xCrx and Fe1−xMox ribbons (x = 0.05, 0.10, 0.15), of potential interest for high-temperature applications and nuclear devices, are investigated in this study in relation to specific processing and annealing routes. The Fe-based thin ribbons have been prepared by induction melting, followed by melt spinning and further annealed in He at temperatures up to 1250 °C. The complex structural, compositional and atomic configuration characterisation has been performed by means of X-ray diffraction (XRD), transmission Mössbauer spectroscopy and differential scanning calorimetry (TG-DSC). The XRD analysis indicates the formation of the desired solid solutions with body-centred cubic (bcc) structure in the as-quenched state. The Mössbauer spectroscopy results have been analysed in terms of the two-shell model. The distribution of Cr/Mo atoms in the first two coordination spheres is not homogeneous, especially after annealing, as supported by the short-range order parameters. In addition, high-temperature annealing treatments give rise to oxidation of Fe (to haematite, maghemite and magnetite) at the surface of the ribbons. Fe1−xCrx alloys are structurally more stable than the Mo counterpart under annealing at 700 °C. Annealing at 1250 °C in He enhances drastically the Cr clustering around Fe nuclei.