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Because of their excellent properties, glass-ceramics have been widely developed and applied in many fields, and there are many potential application values to be disseminated. The preparation of glass-ceramics from industrial slag and metallurgical waste provides a new way for the comprehensive utilization of solid waste. Coal gangue is the largest of all kinds of industrial waste slag, while iron tailings and high-carbon ferrochrome slag also occupy a large proportion of China's industrial solid waste. With cheap industrial solid waste as the main raw material, the production of high-value-added glass-ceramics can reduce pollution, protect the ecological environment, and have good economic and social benefits. Cordierite glass-ceramics were prepared using the sintering method with coal gangue, iron tailings, and high-carbon ferrochrome slag as the main raw materials. Meanwhile, an iron silicon alloy containing chromium was obtained. The heat treatment system of basic glass was determined by differential scanning calorimetry (DSC), and the sintered product was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). An orthogonal test was used to analyze the effects of the mass of basic glass powder, molding pressure, and holding time on the grain size and crystallinity of the samples. The hardness, acid and alkali resistance, density, and water absorption of the sintered products were determined. The results show that the main crystal phase of the prepared glass-ceramics is cordierite. The optimal combination for the green body is "basic glass powder mass 6 g, molding pressure 35 MPa, holding time 10 min". The properties of glass-ceramics are good. At the crystallization temperature of 970 °C, the Vickers hardness is up to 866 HV, and the bulk density is up to 2.99 g/cm3. This study may provide a useful reference for the treatment of industrial solid waste. [ABSTRACT FROM AUTHOR]

Solid iron-silicon alloys play an important role in planetary cores, especially for planets that formed under reducing conditions, such as Mercury. The CsCl (B2) structure occupies a considerable portion of the Fe-Si binary phase diagram at pressure and temperature conditions relevant for the core of Mercury, yet its thermodynamic and thermoelastic properties are poorly known. Here, we report in situ X-ray difraction measurements on iron-silicon alloys with 7–30 wt% Si performed in laser-heated diamond-anvil cells up to ~120 GPa and ~3000 K. Unit-cell volumes of the B2 phase at high pressures and high temperatures have been used to obtain a composition-dependent thermal equation of state of this phase. In turn, the thermal equation of state is exploited to determine the composition of the B2 phase in hcp+B2 mixtures at 30–100 GPa and to place constraints on the hcp+B2/B2 phase boundary, determined to vary between ~13–18 wt% Si in the considered pressure and temperature range. The hcp+B2/B2 boundary of Fe-Si alloys is observed to be dependent on pressure but weakly dependent on temperature. Our results, coupled with literature data on liquid equations of state, yield an estimation of the density contrast between B2 solid and liquid under Mercury's core conditions, which directly relates to the buoyancy of the crystallizing material. While the density contrast may be large enough to form a solid inner core by the gravitational sinking of B2 alloys in a Si-rich core, the density of the B2 solid is close to that of the liquid at solidus conditions for Si concentration approaching ~10 wt% Si. [ABSTRACT FROM AUTHOR]

Ilmenite mud generated in the sulfate process for titanium dioxide pigment production is a secondary titanium resource with a high content of silica, iron oxides, and sulfur. However, the ilmenite mud is mostly landfilled. We propose roasting and high-temperature smelting processes to investigate the reduction behavior of ilmenite mud waste. Sulfur is present in ilmenite mud in the form of sulfates, and is completely removed via roasting. The phases in the roasted ilmenite mud were titanium dioxide, pseudobrookite, and silica. The roasted ilmenite was smelted to recover iron, silicon, and titanium. All the iron oxides were reduced to metallic iron. As a result, the carbothermic reduction of titanium dioxide occurred, and titanium carbide was formed. Silica was first converted into mullite using alumina and then reduced to form liquid silicon, which was combined with metallic iron to form an iron-silicon alloy. After a reduction time of 60 min, most of the silica was converted into the iron-silicon alloy, and the alloy and titanium carbide were completely separated. [ABSTRACT FROM AUTHOR]

Hyperfine parameters of iron nuclei such as isomer shift, quadrupole splitting, and asymmetry parameter are calculated for β -FeSi 2 with and without vacancies, using density functional theory. They are applied, in combination with parameters of α -FeSi 2 obtained earlier, for analyzing Mössbauer and X-ray diffraction experiments on the mechanical alloying of silicon with iron in the range of 1–33 at. % of Fe. Such an approach allows more detailed and precise information to be obtained on the structure of Fe–Si samples. In particular, the fraction of vacancies in α - and β -FeSi 2 is estimated, and the mechanism of formation of these phases and their transformation into each other is discussed. A new model is developed for analyzing experiments on hyperfine interaction, such as Mössbauer spectroscopy, time-differential perturbed-angular correlation, and the like, for Fe–Si systems with a high Si content. [ABSTRACT FROM AUTHOR]

Because of the existence of B2 and DO3 ordered phases with high hardness and brittleness, the poor plasticity at room temperature brings some difficulties for the industrial production of high silicon steels. The influence of La as a microalloying element on order–disorder transformation and deformation softening behavior of Fe–6.5 wt % Si alloy was studied during warm rolling. The solid drag effect of La reduced the ability of Fe and Si atoms to diffuse to neighboring vacancies in ordered structures, and hindered the nucleation and growth of the B2 ordered phase, resulting in a decrease in the content of B2 phase and size of its particles. Moreover, DSC results indicated that the disappearance of DO3 ordered phase was attributable to the change in order-disorder transformation temperature. The values of nano-hardness decreased from 11.2 GPa for non-La-doped alloy to 5.3 GPa for La-doped alloy, which indicated that the deformation softening ability of Fe–6.5 wt % Si alloy was significantly improved by adding rare earth La. [ABSTRACT FROM AUTHOR]

Knowledge of the sound velocity of core materials is essential to explain the observed anomalously low shear wave velocity (VS) and high Poisson's ratio (σ) in the solid inner core. To date, neither VS nor σ of Fe and Fe-Si alloy have been measured under core conditions. Here, we present VS and σ derived from direct measurements of the compressional wave velocity, bulk sound velocity, and density of Fe and Fe-8.6 wt%Si up to ~230 GPa and ~5400 K. The new data show that neither the effect of temperature nor incorporation of Si would be sufficient to explain the observed low VS and high σ of the inner core. A possible solution would add carbon (C) into the solid inner core that could further decrease VS and increase σ. However, the physical property-based Fe-Si-C core models seemingly conflict with the partitioning behavior of Si and C between liquid and solid Fe. The origin of the observed low shear wave velocity in the solid inner core is unclear. Here, the authors report shear wave velocities of iron and iron-silicon alloy under Earth's core conditions by shock compression and find that neither the effect of temperature nor incorporation of Si can explain observed low shear wave velocity in the inner core. [ABSTRACT FROM AUTHOR]

Mercury's metallic core is expected to have formed under highly reducing conditions, resulting in the presence of significant quantities of silicon alloyed to iron. Here we present the phase diagram of the Fe-FeSi system, reconstructed from in situ X-ray diffraction measurements at pressure and temperature conditions spanning over those expected for Mercury's core, and ex situ chemical analysis of recovered samples. Under high pressure, we do not observe a miscibility gap between the cubic fcc and B2 structures, but rather the formation of a re-entrant bcc phase at temperatures close to melting. Upon melting, the investigated alloys are observed to evolve towards two distinct Fe-rich and Fe-poor liquid compositions at pressures below 35-38 GPa. The evolution of the phase diagram with pressure and temperature prescribes a range of possible core crystallization regimes, with strong dependence on the Si abundance of the core. The iron-silicon phase diagram has been established at the conditions of Mercury's core. The resulting phase diagram is remarkably complex, and presents an array of new mechanisms which may power Mercury's inner dynamo. [ABSTRACT FROM AUTHOR]

A sulfuric acid system was used to recover Co from cobalt white alloy, and the leached cobalt was electrochemically dissolved.i This is a key step to separate the iron-silicon alloy phase from valuable metals when leaching cobalt white alloys with high silicon and iron contents. As an additive, sodium hypochlorite (NaClO) acts as an oxidant to break cobalt encapsulation and enhances leaching. It generates chloride ions, which further enhance Co leaching based on their corrosive ability. The results showed that the maximum leaching ratio of Co from the waste cobalt white alloy was 97.76%. Kinetic analysis showed that the apparent activation energy of Co leaching was 34.58 kJ/mol, and the surface chemical reaction was a controlling step for this process. The kinetic equation for the leaching of Co can be expressed as 1 - 1 - α 1 3 = 0.065 t × r 0 - 1 × H 2 SO 4 2.44 × exp - 34580 8.314 T . [ABSTRACT FROM AUTHOR]

The purpose of the study is to propose a thermodynamic description of the full magneto-mechanical coupling in electrical steel sheets, including both elasticity and plasticity influence. Kinematic and isotropic hardening are considered as state variables and included to a second-order magneto-elastic energy written as a function of cubic invariants. The simulation of magnetic behaviour of plastified samples subjected to several elastic stresses reproduce the general trends of measurements carried out on non-oriented Fe-3%Si sheets. • A multiaxial and multiscale description of the magneto-elasto-plastic coupling is proposed. • The influence of kinematic and isotropic hardening is taken into account with one new parameter. • This study opening up the possibility of non-destructive measurements of both hardenings. [ABSTRACT FROM AUTHOR]

• Optimized laser sintering parameters were determined for Fe-6.5 wt%Si alloy based on microstructural and magnetic measurements, • We have developed a unique building platform with an elevated table temperature of up to 450 °C, • Subsequent heat treatment can successfully improve soft magnetic properties. Optimization of 3D printing parameters was studied for the difficult to print, brittle Fe-6.5 wt%Si, applying powder bed fusion (PBF) technology. Printing orientation, volumetric energy density (VED), built plate (BP) temperature, as deposition parameters and the influence of post-deposition heat treatment (HT), were investigated. The optimal parameters were established based on the EBSD figures of samples deposited in different orientations, optical microscopy images, CT measurements, DC hysteresis curves, complex permeability spectra, and XRD patterns. [ABSTRACT FROM AUTHOR]

One-dimensional (1D) chain-like nanocomposites, created by ensembles of nanoparticles of with diameter ~13 nm, which are composed of an iron core (~4 nm) and a silica protective layer, were prepared by a self-assembly process. Chain-like Fe@SiO2 ensembles were formed due to strong magnetic dipole-dipole interactions between individual Fe nanoparticles and the subsequent fixation of the Fe particles by the SiO2 layers. X-ray near edge absorption spectra measurements at the Fe K absorption edge confirm that the presence of a silica layer prevents the oxidation of the magnetic Fe core. Strong magnetic interactions between Fe cores lead to long-range ordering of magnetic moments, and the nanoparticle ensembles exhibit superferromagnetic characteristics demonstrated by a broad blocking Zero-field cooling (ZFC)/field-cooling distribution, nearly constant temperature dependence of ZFC magnetization, and non-zero coercivity at room temperature. Low room-temperature coercivity and the presence of electrically insulating SiO2 shells surrounding the Fe core make the studied samples suitable candidates for microelectronic applications. [ABSTRACT FROM AUTHOR]

Amongst the most important graphite shapes, nodules and compacted particles are of particular interest as they can coexist in castings with relevant changes in properties. In this context, it has been often reported that the compacted shape is an intermediate form between nodules and graphite lamellas that may be seen as degeneracy from the nodular one. The present work shows the microstructure evolution of an initially ductile iron alloy with a silicon content of about 2.4 wt% when reducing progressively the magnesium content by holding a large melt batch in a nitrogen-pressurized pouring unit for 8 h. Thermal cups with and without inoculant were cast at a regular time interval together with a sample for chemical analysis. Interestingly, the thermal records of the inoculated samples show no significant changes with time while the structure evolved from fully spheroidal to half-spheroidal half-compacted graphite. Conversely, the thermal curves of the non-inoculated samples showed two arrests, one at nearly the same temperature as for inoculated alloys and a second one at a temperature decreasing with holding time until being below the metastable eutectic temperature. Microstructure observations showed the presence of a limited number of compacted cells which decreases as well with holding time. These observations suggest that these cells start developing during the temperature interval between the first and second arrests, leading to a bulk eutectic transformation either above or below the metastable eutectic temperature. These results support the view that a fully compacted structure can be obtained only with a controlled inoculation which should not be too high to avoid too high nodularity. [ABSTRACT FROM AUTHOR]

The formation processes of iron silicide nanoparticles dependent on thermal annealing were examined by ex situ and in situ transmission electron microscopy (TEM). An Fe thin film with a thickness of ∼2 nm was deposited on a Si(100) substrate at room temperature using an electron-beam evaporation method, followed by thermal annealing at temperatures ranging from 573 to 1173 K. Ex situ TEM observations showed that pyramidal β-FeSi2 particles (1173 K) were formed via the [variant_greek_epsilon]-FeSi layer (573 K) and the γ-FeSi2 particle (873 K). Detailed observations by in situ TEM indicated that an amorphous Fe-Si layer was formed on the Si substrate in the as-deposited specimen. This amorphous layer was crystallized into [variant_greek_epsilon]-FeSi after thermal annealing and then hemispherical [variant_greek_epsilon]-FeSi particles together with metastable γ-FeSi2 were formed just beneath the surface of the Si substrate. With increasing annealing temperature, the [variant_greek_epsilon] phase changed to hemispherical γ-FeSi2 nanoparticles and finally the γ-FeSi2 particles transformed into pyramidal β-FeSi2 particles. We discuss the formation mechanism of the iron silicide nanoparticles at the atomic scale. [ABSTRACT FROM AUTHOR]

Si/β-FeSi 2-particles/Si structures have been fabricated by reactive deposition epitaxy forβ-FeSi 2 and molecular-beam epitaxy (MBE) for Si, and the influence of the size of theβ-FeSi 2 panicle and the MBE-Si growth rate for embedding theβ-FeSi 2 in Si on 1.5-µ m photoluminescence (PL) intensity ofβ-FeSi 2 was investigated. The 1.5-µ m PL intensity was observed to increase with the size of theβ-FeSi 2 panicle, but the broad background luminescence, ranging from 1.2 to 1.4µ m, also increased. Transmission electron microscopy observation suggested that the broad luminescence was due to the dislocations induced in the Si matrix when the size of the embeddedβ-FeSi 2 panicles was too large. Furthermore, the 1.5-µ m PL intensity was observed to be strongly affected by MBE-Si growth rate. This is thought to be due to the strain induced in theβ-FeSi 2 panicles upon being embedded in the Si. [ABSTRACT FROM AUTHOR]

Focuses on a study which evaluated the electrical properties of iron-silica nanocomposites synthesized by electrodeposition. Details on the electrodeposition method employed in the study; Theories proposed to explain the alternating current conductivity behavior in amorphous materials; Conclusion.

Current transformers (CTs) are extensively used for the measurement of electrical energy, and hence they play a crucial role in the revenue generation for power distribution utilities. The novelty of this paper is that it presents artificial neural network (ANN) application for the ratio and phase angle error corrections of CTs in the presence of harmonic distortions. In this paper, the behaviors of silicon iron alloy and nanocrystalline alloy CTs are examined by the means of a number of experimental tests under the sinusoidal and distorted waveform conditions. The relation between the nature of CTs secondary current waveforms (CTSwf) with their metrological properties, connected burdens, and nature of load currents (linear or nonlinear) is established. The training data are obtained by the nature of CTSwf in terms of amplitude errors, time shifts, and deviations caused by different harmonic contents between input and output quantities. The ANN is trained for various operating conditions. The implementation of the error correction system and data acquisition is done using dSPACE 1104 software. The experimental results illustrate that the proposed technique can be used for error compensation in case of sinusoidal and the distorted waveform composed of fundamental and many harmonics. [ABSTRACT FROM AUTHOR]

The elasticity of hcp‐Fe‐5wt%Si has been investigated by synchrotron X‐ray diffraction up to 110 GPa and 2,100 K and by picosecond acoustics measurements at ambient temperature up to 115 GPa. The established Pressure‐Volume‐Temperature equation of state shows that the density of the Earth's inner core can be matched by an Fe‐Si alloy with 5wt% Si for all reasonable core temperatures, but that its compressional and shear velocities remain too high with respect to seismological observations. On the other hand, Fe‐Si alloys whose velocities are expected to get close to seismological observations are too dense at relevant temperatures. Thus, based on these combined velocity‐density measurements, silicon is not likely to be the sole light element in the inner core. Plain Language Summary: Combining measurements of sound velocity and density at high pressures and temperatures shows that while Fe‐5wt% Si can match the density profile of the Earth's inner core, its sound velocity is too high with respect to seismological observations. Key Points: Isothermal compression of Fe‐5wt%Si at high temperatures up to 1.1 Mbar and 2100 KMeasurement of Vp of Fe‐5wt%Si under quasihydrostatic conditions to 1.1 MbarSi cannot be the sole light element in the Earth's inner core [ABSTRACT FROM AUTHOR]

This paper aims to study the properties of ferromagnetic alloys obtained by powder metallurgy for the construction of cores of a servomotor, usually assembled from rolled steel sheets. The raw material used was pure iron powder and alloys obtained by mixing with different percentages of phosphorus (1, 2 and 3%), silicon (1, 3 and 5%) and nickel (50%). The material characterization involved tests of the main magnetic, electrical and mechanical properties of these alloys. The results obtained for the magnetic properties showed that the sintered alloys have lower values than the cores of plates. However, smaller losses were observed due to the increase in resistivity for the addition of phosphorus, silicon and nickel in the iron alloys. In the tests of magnetic losses in cores, it was observed that in low frequencies the sintered material presented significant losses, already in high frequencies behaved in a similar way to the cores of plates. [ABSTRACT FROM AUTHOR]

Crystallographic calculations using the edge-to-edge matching (E2EM) model indicated a high grain refining potency of Ce2O2S for primary δ-ferrite during solidification of associated steels because of the low interatomic spacing misfit of 4.27 pct along the matching directions of 21¯1¯0Ce2O2S||110δ- Fe and the low interplanar mismatch of 4.27 pct between the matching planes of {112¯0}Ce2O2S||{011}δ- Fe. To verify this prediction, an Fe-4Si alloy was selected as the test alloy to enable the retention of the primary δ-ferrite at room temperature. The appropriate Ce addition was predicted with thermodynamic calculations using the FactSage Software System based on the sulfur content in the alloy. Compared with that of the alloy without Ce, the addition of 0.0325 wt pct Ce led to a 47.1 pct reduction in the average grain size in the Fe-4Si alloy ingots. Calculations based on the E2EM model also predicted two novel orientation relationships (ORs) between Ce2O2S and the primary δ-ferrite. These two ORs were also experimentally observed using electron backscattered diffraction in a scanning electron microscope. The ORs are as follows: [21¯1¯0]Ce2O2S||[110]δ- Fe, (0002¯)Ce2O2S1.0 deg from (11¯0)δ- Fe, (011¯0)Ce2O2S1.0 deg from (002)δ- Fe and [1¯101]Ce2O2S||[100]δ- Fe, (112¯0)Ce2O2S3.0 deg from (01¯1¯)δ- Fe, (1¯102¯)Ce2O2S3.0 deg from (01¯1)δ- Fe. [ABSTRACT FROM AUTHOR]

Abstract Utilization of coal fly ash (CFA) has attracted extensive attentions in the last decades because of the increasing awareness of environmental protection and waste recovery. In the present paper, a new treatment process for utilization of CFA by extracting alumina and preparing Fe-Si alloys was proposed. The main procedures of the process contain carbothermic reduction and magnetic separation. Both of the thermodynamic analysis and experimental results show that an addition of Fe 2 O 3 can significantly cut down the reduction temperature and strongly enhance the decomposition of stable mullite phase (Al 6 Si 2 O 13) in CFA. Scanning electron microscopy (SEM) analysis with energy dispersive spectroscopy (EDS) demonstrated that spherical Fe-Si alloys were formed adjacent to the alumina (obtained from the decomposition of mullite) during the carbothermic reduction. The alumina and Fe-Si alloys in the reduced sample can be effectively separated by the subsequent magnetic separation, and the mass fraction of alumina in the non-magnetic part reached 91.33%. Compared with the conventional sinter process and acid leaching process, carbothermic reduction method with addition of Fe 2 O 3 for extracting aluminum makes fewer residues, which may provide a new idea for large-scale utilization of CFA. Highlights • A new process for extracting alumina and preparing Fe-Si alloy from CFA is proposed. • An addition of Fe 2 O 3 can significantly cut down the reduction temperature of CFA. • The addition of Fe 2 O 3 can also enhance the decomposition of mullite in CFA. • Silicon in quartz and mullite was transformed into the byproduct Fe-Si alloys. • Fe-Si alloys and alumina can be effectively separated by magnetic separation. [ABSTRACT FROM AUTHOR]

The Rayleigh-Taylor (RT) instability of liquid iron alloys is important for understanding the core formation mechanism in the Earth. Here we first report the measurement of RT instability growth for a liquid iron-silicon (Fe-Si) alloy, which is one of the major candidate for the material of the Earth's core, using a high power laser. We optimized the measurement setup and analytical technique to observe the growth of perturbation on an Fe-Si sample surface. The growth of perturbation amplitude on the Fe-Si alloy under high pressure and temperature was successfully observed using in situ X-ray radiography. The growth rate of the RT instability for the Fe-Si alloy on about 1000 GPa was estimated to be 0.3 ns−1. [ABSTRACT FROM AUTHOR]

Abstract Iron−silicon steels have excellent magnetic and electrical properties, especially, with increased silicon and aluminum contents. However, increasing alloying with Si and Al reduces the workability of the material, and spontaneous cleavage fracture may occur during production. The main influence factors on the occurrence of cleavage fracture of Fe−Si−Al alloys are investigated in this paper. Fracture mechanics tests are performed at various temperatures and loading rates. The effects of specimen orientation and strain aging are studied. The tests result surprisingly high fracture toughness values. However, cleavage fracture regions are found in the pre-fatigue regions of the specimens, i.e. at much lower loads. In order to resolve this effect, the strain rates during the various fatigue- and fracture experiments are estimated by an analytical model. Additional fatigue experiments are performed at various frequencies where the stress intensity range is increased until cleavage fracture is detected. Similar experiments are conducted at increasing temperatures. The analyses reveal a significant transition behavior of the stress intensity at the onset of cleavage fracture, where the effects of decreasing temperatures and increasing strain rates are equivalent. Measures for avoiding cleavage fracture can be deduced from the results of this investigation. [ABSTRACT FROM AUTHOR]

Highlights • The PL intensity from β-FeSi 2 was enhanced by pre-coating silver on Si substrates. • A modified-Si surface due to Ag diffusion was reconstructed into domain structure. • This mechanism decreased the non-radiative recombination centers density in β-FeSi 2. Abstract The improving of the crystal quality and pronounced enhancement of photoluminescence intensity from β-FeSi 2 were achieved by pre-coating silver (Ag) layers on Si(1 0 0) substrates. A modified-Si surface, which formed during the heating step before β-FeSi 2 deposition due to Ag diffusion, was reconstructed the surface into domain structure that minimize the strain caused by lattice matching of β-FeSi 2 and Si. This mechanism led to the formation of β-FeSi 2 film with very low levels of density of non-radiative recombination centers, and led to the pronounced enhancement of PL intensity. [ABSTRACT FROM AUTHOR]

Abstract The microstructural evolution of Fe-6.5 wt.% Si alloy during rapid solidification was studied over a quenching rate of 4 × 104 K/s to 8 × 105 K/s. The solidification and solid-state diffusional transformation processes during rapid cooling were analyzed via thermodynamic and kinetic calculations. The Allen-Cahn theory was adapted to model the experimentally measured bcc_B2 antiphase domain sizes under different cooling rates. The model was calibrated based on the experimentally determined bcc_B2 antiphase domain sizes for different wheel speeds and the resulting cooling rates. Good correspondence of the theoretical and experimental data was obtained over the entire experimental range of cooling rates. Along with the asymptotic domain size value at the infinite cooling rates, the developed model represents a reliable extrapolation for the cooling rate > 106 K/s and allows one to optimize the quenching process. Highlights • New Fe-6.5 wt.% Si melt spinning experiments and cooling rate measurements. • The melt spun ribbons were characterized using TEM analysis. • Solidification and solid-state transformation during rapid quenching were analyzed. • The bcc_B2 domain growth was modeled using the Allen-Cahn theory. [ABSTRACT FROM AUTHOR]

Abstract The low retainability of reinforcing particles in functional composite coatings fabricated by cold spray (CS) is a major problem in maximizing coating properties. In this work, the Ni-coated FeSiAl composite powders were used to fabricate soft magnetic composite (SMC) coatings via CS. The feedstock particles were preheated prior to the entrance of nozzle to improve the retainability of FeSiAl particles and the coating properties. Our results showed that the dense Ni/FeSiAl coatings containing the uniformly-dispersed and crack-free FeSiAl particles were produced. The thermal softening effect of Ni layer, as a result of particle preheating, can effectively increase the volumetric content of FeSiAl particle (from 24.3% to 46.2%) in the composite coating. Particle preheating also conducted to the significant improvement of coating thickness due to enhanced deposition efficiency. Dry-sliding test showed that the tribological performance of SMC coating with particle preheating weakens, owing to lowered microhardness. Enhanced magnetic property was achieved with higher soft ferromagnetic characteristic and decreasing coercivity value at higher particle preheating temperatures. The study on coating formation mechanism highlighted that thermal softening effect can give rise to adiabatic shear instability of Ni layer. This results in the significantly improved retainability of FeSiAl particles and soft magnetic performance. Graphical abstract Unlabelled Image Highlights • Ni-coated FeSiAl powder was used to fabricate soft magnetic composite coating by cold spraying. • Higher retainability of FeSiAl particles was achieved by particle preheating. • Tribological performance of the Ni/FeSiAl composite coatings with particle preheating was studied. • Soft magnetic performance was enhanced at higher particle preheating temperatures. • The thermal softening effect of preheated composite particles was discussed. [ABSTRACT FROM AUTHOR]

Abstract Two metallurgical purification techniques, namely solvent refining and slag treatment, were combined to remove boron from silicon. Silicon was alloyed with iron and the alloy was subjected to slag treatment by a ternary of CaO-SiO 2 -Al 2 O 3 at 1600 °C (1873 K). Effects of oxygen potential and basicity of slag on boron removal were investigated through changing the SiO 2 /Al 2 O 3 and CaO/SiO 2 ratios, respectively. Results indicate that these two parameters have major effects on partition ratio of boron. A critical oxygen potential value, which yields the highest partition ratio of boron, was calculated as approximately 9 × 10−18 atm. Partition ratio of boron was normalized with oxygen potential at each slag composition in order to isolate the effect of basicity. Borate capacity values were calculated for different slags and it was shown that this parameter is only a function of temperature and slag composition. The kinetics of boron removal was quantified and the total mass transfer coefficient of boron was calculated as 7.48 × 10−6 cm/s. Highlights • A metallurgical method was applied for boron removal from silicon. • A critical oxygen potential, that yields the highest boron removal, was calculated. • Boron distribution was normalized by oxygen potential at each slag composition. • Total mass transfer coefficient of boron was calculated by a kinetic analysis. [ABSTRACT FROM AUTHOR]

With the so-called green transition of contemporary society, the need for efficient, lightweight, and durable electrical machines and devices is more crucial than ever. High-silicon Fe-alloys and steels are regarded as the most suitable materials for their production as they possess the following properties: * high permeability and induction; * low power losses; * low magnetostriction. However, as the Si content in these alloys exceeds 5 wt.%, the material becomes brittle and the conventional metallurgical cold processing into thin sheets is not possible anymore. Our project is focusing on optimizing process parameters of additive manufacturing - selective laser melting (AM-SLM), and the selection of the post-processing steps aimed to enhance not only the electromagnetic and mechanical properties of the material, but also the printability into desired geometries. Optimization takes place by iterating adjusted processing parameters of AM-SLM (and subsequent annealing) to control the texture, analyzing the resulting metallographic and electromagnetic (EM) properties, while also adapting and optimizing the evaluation steps. [ABSTRACT FROM AUTHOR]

Powder bed fusion of metal with laser beam (PBF-LB) of application-ready parts of iron-silicon alloys with a high silicon content is both promising and challenging. Although a higher silicon content significantly improves the soft-magnetic behaviour, it also promotes brittleness and thus, makes these alloys barely suitable for the production of parts with a height larger than a few millimetres. To overcome these challenges, the potential of a build-chamber preheating system implemented in a standard PBF-LB machine is investigated in terms of the defect- and crack-free manufacturing of large-scale samples and components of brittle iron-silicon alloys. In addition, the current study analyses the influence of the silicon content on the soft-magnetic and mechanical behaviour of additively processed iron-silicon alloys. For this purpose, four alloys with a silicon content between 2.4 wt.-% and 10.0 wt.-% are processed into samples with different dimensions. Subsequently, the manufactured samples are heat-treated and the resulting influence of both, the Si-content and the heat treatment on the microstructure as well as the soft-magnetic and mechanical properties are analyzed. As it is shown, defect- and crack-free parts can be manufactured independently of the dimensions. Iron alloyed with 6.7 wt.-% of Si exhibits the best permeability of all investigated alloys, which can be further improved up to 1.5 times by applying a suitable heat treatment. Thus, the results obtained build a basis for powder bed fusion of application-adapted parts with outstanding soft-magnetic properties, which can be barely manufactured using conventional forming technologies. [ABSTRACT FROM AUTHOR]

The Heusler compound Co2FeSi is a prospective half-metallic material for spintronic applications. Defects and antisite disordering play a crucial role among the factors reducing spin polarization in such materials. To clarify effects of possible off-stoichiometry, a continuous series of model solid solutions Co3-xFexSi (0.6⩽x⩽1.4) was investigated by 57Fe Mössbauer spectroscopy and 59Co nuclear magnetic resonance. It has been shown that the hyperfine magnetic fields on Fe can be used to monitor Co-Fe disordering in Co2FeSi-based bulk samples and thin films. [ABSTRACT FROM AUTHOR]

We demonstrate high-quality epitaxial growth of Heusler alloy Co2FeSi on Ge(111) by molecular beam epitaxy (MBE) at 200 °C. Even for growth at such a low temperature, L21-ordered crystal structure is formed and highly uniform magnetic environments around the Fe sites are realized, by transmission electron diffraction and conversion electron Mössbauer spectroscopy, respectively. We also find that the magnetic moment reaches 5.37 μB/ f.u., which is the highest value in thin-film Co2FeSi samples reported. [ABSTRACT FROM AUTHOR]

The authors developed a fabrication technique of Co2FeSi/SiOxNy / Si tunnel junctions, employing rapid thermal annealing (RTA). The full-Heusler Co2FeSi (CFS) alloy thin film was directly formed on the ultrathin SiOxNy barrier layer without a buffer layer by RTA-induced silicidation reaction of a Co/Fe/amorphous-Si multilayer deposited on the barrier layer. The ultrathin SiOxNy layer formed on a Si substrate effectively blocked the diffusion of Co and Fe atoms into the Si substrate, leading to the formation of a high quality tunnel junction. It was found from crystallographic analyses that the CFS film on SiOxNy has a highly (110)-oriented texture structure with the L21 ordering and the CFS/SiOxNy interface was atomically flat without intermixing and crystallinity degradation. [ABSTRACT FROM AUTHOR]

The melt-spun Fe83.3–84.3Si4B8P3–4Cu0.7 alloys have a heterogeneous amorphous structure including a large amount of α-Fe-like clusters. Compared with the FeSiB alloys, the particle size rapidly decreases from several hundred nanometers to 2–3 nm due to the proper amounts of simultaneous P and Cu additions. By controlling the crystallization process, a homogeneous nanocrystalline structure composed by small α-Fe grains with size of 10–17 nm in diameter can be realized from the heterogeneous amorphous alloys. The nanocrystallized Fe83.3–84.3Si4B8P3–4Cu0.7 alloys show the extremely high saturation magnetic flux density of 1.88–1.94 T sufficiently near to 1.97 T of Fe-3.5 mass %Si crystalline soft magnetic alloys, and exhibit low coercivity of less than 10 A/m and higher effective permeability of 16 000–25 000 at 1 kHz due to the simultaneous realization of the homogeneous nanocrystalline structure and the small magnetostriction of (2–3)×10-6. In addition, the nanocrystalline alloys exhibit the superior core loss to the representative Fe78Si9B13 amorphous alloy at 50 Hz. [ABSTRACT FROM AUTHOR]

The effect of B to Si concentration ratio on the glass-forming ability (GFA) and soft-magnetic properties of (Co0.705Fe0.045B0.25-xSix)96Nb4 (x=0.02–0.1) alloys was investigated. The (Co0.705Fe0.045B0.25-xSix)96Nb4 bulk glassy alloys with diameters up to 2 mm were synthesized in the composition range of x=0.02–0.06. In addition to high GFA, the Co-based glassy alloys exhibit excellent soft-magnetic properties as well, i.e., rather high saturation magnetization of 0.62 T, low coercive force of 0.6–1 A/m, and superhigh initial permeabilities of 37 100–53 700 at 1 kHz under a field of 1 A/m. The alloys with Si contents of x=0.05 and 0.06 exhibit high initial permeabilities of 29 300 and 24 300, respectively, even at 100 kHz. [ABSTRACT FROM AUTHOR]

A set of experimental devices was designed and built to investigate the effects of average temperature of lamination, contact pressure, and lamination number on the effective axial thermal conductivity of silicon steel multi-stacked material in the loading and unloading processes under atmospheric environment. Specimens are stacked by oriented silicon steel sheets, the content of silicon is approximately 3.3%, and thickness is 0.23 mm. Average temperature is in the range of 200–800 °C, and contact pressure is between 0.16 and 16.68 MPa. Experimental results indicated that: effective axial thermal conductivity presented an obvious relationship with the average temperature and contact pressure of lamination but showed independence from the lamination number. Effective axial thermal conductivity is more sensitive to contact pressure in the loading process than in the unloading process. The correlation equations of effective axial thermal conductivity have an accuracy of 15%. [ABSTRACT FROM AUTHOR]

Grain refinement is an effective technique to improve the mechanical properties of steels. In the present work, single-pass hot compression experiments have been conducted on two different compositions of high phosphorous steels to study the microstructural evolution and ferrite grain refinement at various strain rates and deformation temperatures, i.e., 0.01-10 s−1 and 750-1050 °C, respectively. Optical metallography has been employed to understand the physical processes that take place during hot deformation process. The results indicate that when these compositions of high phosphorous steels are worked at relatively low temperatures in the intercritical regions, a ferrite grain size of 5-7 µm is obtained. It is observed that the grain size decreases with an increase in strain rate and with the decrease in deformation temperature. Based on the values of stress exponent (n) obtained in the present work, dislocation creep is identified as the deformation mechanism. The activation energies for deformation of these two types of high phosphorous steels have been calculated. The effect of the alloying elements on the stress-strain curve, microstructure, and grain refinement has been discussed. [ABSTRACT FROM AUTHOR]

The treatment of relatively inexpensive silicon-iron alloys is a potential refining route in order to generate solar-grade silicon. Phosphorus is one of the more difficult impurity elements to remove by conventional processing. In this study, electromagnetic levitation was used to investigate phosphorus behavior in silicon-iron alloy droplets exposed to H2-Ar gas mixtures under various experimental conditions including, refining time, temperature (1723 K to 1993 K), gas flow rate, iron content, and initial phosphorus concentration in the alloy. Thermodynamic modeling of the dephosphorization reaction permitted prediction of the various gaseous products and indicated that diatomic phosphorus is the dominant species formed. [ABSTRACT FROM AUTHOR]

The effects of Cr addition on the thermal stability, soft magnetic properties and corrosion resistance of Fe 79.5-x Si 9.5 B 11 Cr x amorphous alloys were detailed investigated. It was found that Cr addition has multiple effects on improving those properties of FeSiB amorphous alloys. As Cr content increases from 0 to 5 at%, the coercive force decreases from 2.46 to 2.02 A/m, and the corrosion rate of the alloys in 0.1 M NaCl solution also decreases from 1.83 × 10 −1 to 3.91 × 10 −4  mm·year −1 . Besides, the passive region exceeds 1.13 V for the alloy containing 7 at% of Cr. [ABSTRACT FROM AUTHOR]

This study investigated Fe-17 at% P addition effects on the magnetic properties of Fe-3.5 wt% Si alloys to enhance the electrical resistivity and core loss in powder injection molding. Considering the lowest melting point for 17 at% of P in the Fe-P phase diagram, the effect of P in Fe-3.5 wt% Si was analyzed by adding Fe-17 at% P from 0 to 12 wt% with 4 wt% increments. The feedstocks were prepared based on the processing optimization with respect to the critical solid loading, mixing homogeneity, and binder decomposition. The microstructure; relative density; electrical resistivity; and C, O, N, and S impurities of the sintered alloys were analyzed in correlation with the magnetic properties. The magnetic induction (B 5000 ), maximum permeability, coercivity at 400 Hz and core loss in the frequency range from 50 to 1000 Hz at 1 T were analyzed. The higher magnetic induction and the lower eddy current loss with increasing Fe-17 at% P addition were induced by the higher relative density and electrical resistivity, respectively. [ABSTRACT FROM AUTHOR]

Fe-Si electric steel is the most widely used soft magnetic material in electric machines and transformers. Increasing the silicon content from 3.2 wt.% to 6.5 wt.% brings about large improvement in the magnetic and electrical properties. However, 6.5 wt.% silicon steel is inherited with brittleness owing to the formation of B2 and D03 ordered phase. To obtain ductility in Fe-6.5wt.% silicon steel, the ordered phase has to be bypassed with methods like rapid cooling. In present paper, the effect of cooling rate on magnetic and mechanical properties of Fe-6.5wt.% silicon steel is studied by tuning the wheel speed during melt spinning process. The cooling rate significantly alters the ordering and microstructure, and thus the mechanical and magnetic properties. X-ray diffraction data shows that D03 ordering was fully suppressed at high wheel speeds but starts to nucleate at 10m/s and below, which correlates with the increase of Young’s modulus towards low wheel speeds as tested by nanoindentation. The grain sizes of the ribbons on the wheel side decrease with increasing wheel speeds, ranging from ∼100 μm at 1m/s to ∼8 μm at 30m/s, which lead to changes in coercivity. [ABSTRACT FROM AUTHOR]

We investigated the ambient temperature structural properties (thickness, width, microstructure, and lattice parameter), and the ambient and high temperature (up to 900 K) direct current (DC) magnetic properties—saturation magnetization ( M S ) and intrinsic coercivity ( H CI )—of rapidly-solidified (melt-spun) Fe- x wt.% Si ( x = 3, 5, & 8) alloys. The wheel surface speeds selected for the study were 30 m/s and 40 m/s. The ribbons produced at the lower wheel surface speed (30 m/s) were continuous having relatively uniform edges compared to the ribbons produced at the higher wheel surface speed. The thickness and the width of the melt-spun ribbons ranged between ∼15 and 60 μm and 500–800 μm, respectively. The x-ray diffraction spectra of the melt-spun ribbons indicated the presence of disordered α -phase, irrespective of the composition, and the wheel surface speed. The lattice parameter decreased gradually as a function of increasing silicon content from ∼0.2862 nm (Fe-3 wt.% Si) to ∼0.2847 nm (Fe-8 wt.% Si). The wheel surface speed showed an insignificant effect on M S while increased silicon content resulted in a decreasing trend in M S . Elevated temperature evaluation of the magnetization ( M - T curves at ∼7.96 kA/m) in the case of Fe-3 & 5 wt.% Si alloy ribbons was distinctly different from that of the Fe-8 wt.% Si alloy ribbons. The curves of the as-prepared Fe-3 wt.% Si and Fe-5 wt.% Si alloy ribbons were irreversible while that of Fe-8 wt.% Si was reversible. The M S for any of the combinations of wheel surface speed and composition decreased monotonically with the increase in temperature (from 300 to 900 K). While H CI increased with the increase in temperature for all the wheel surface speed and composition combination, its nature of increase is distinct for Fe-8 wt.% Si alloy ribbons compared to Fe-3 & 5 wt.% Si alloys ribbons. It appears that rapidly-solidified Fe-3 wt.% Si and Fe-5 wt.% Si alloys ribbons are primarily comprised of the α -phase (disordered phase) while the Fe-8 wt.% Si alloy ribbons are comprised primarily of disordered phase along with minor constituents of an ordered phase. [ABSTRACT FROM AUTHOR]

High-grade non-oriented electrical steel was successfully processed by controlling texture using strip casting technology. Remarkable abnormal grain growth of {100} grains occurred in the as-cast strip after isothermal annealing. This phenomenon is considered to be the synergistic effect involving the size advantage of coarse columnar grains and surface energy, where the normal grain growth was inhibited by thermal grooving in the surface layer. Special rotation path was identified during the cold rolling process and metastable {118} 〈110〉–{113} 〈110〉 texture dominated the deformation texture. The final annealed sheet exhibited strong Cube texture together with significantly superior magnetic properties. [ABSTRACT FROM AUTHOR]

The article presents a study on crystal structure and equation of state of iron-silicon alloys at super-Earth core conditions. It combine laser-driven dynamic ramp compression with in situ x-ray diffraction to study the effect of composition on the crystal structure and density of the alloys. The study allow for direct determination of the effects of light elements on core radius, density, and pressures for these planets.

The magnetic properties of fully processed non-oriented FeSi electrical steel are characterized by their magnetization behavior and specific magnetic losses. The magnetic properties are determined by the texture and microstructure. Less gamma fiber intensity and a high intensity of preferable texture components, especially cube fiber texture, are desirable to obtain an excellent magnetizing behavior. Furthermore, large grain sizes are necessary to reach low values of the specific magnetic losses. The fabrication route of the fully processed non-oriented electrical steels comprises a heavy cold rolling of the hot rolled material before final annealing. To fulfill the requirements on large grain size for low loss materials, grain growth, which appears after complete recrystallization, plays an important role. In this paper we will analyze the influence of different microstructures of the hot strip and the resulting microstructure after cold rolling on the appearance of recrystallization and grain growth after final annealing. The evolution of texture reflects the present ongoing softening processes: recovery, recrystallization and finally grain growth at the given annealing conditions. It will be shown that the image of texture at recrystallization is remarkable different from the texture at grain growth. Substantially grain growth is obtained at lower annealing temperatures for an optimum microstructure of the hot rolled material. [ABSTRACT FROM AUTHOR]

The β-FeSi 2 /Si semiconducting nanocomposite is a promising thermoelectric system with eco-friendly materials. We show that small quantities of Ge can enhance the thermoelectric properties and widen the design space, if Ge content and spatial disposition can be controlled. We investigated the use of solidification combined with solid-state transformations to reduce the thermal conductivity via hierarchical modification of microstructure. Solidification of Fe 28 Si 68 Ge 4 alloys leads to eutectic lamellar microstructure comprised of hyperstoichiometric α-FeSi 2+δ phase and diamond cubic Si 1-x Ge x . The eutectic lengthscales can be varied over two orders of magnitude depending on solidification rate. Subsequent aging of the eutectic produces eutectoid decomposition, α-FeSi 2 → β-FeSi 2 + Si 1-y Ge y , where the additional diamond cubic product is interleaved with the eutectic lamellae. By controlling both the frequency of β-FeSi 2 /diamond cubic heterointerfaces, as well as the degree of Ge segregation into the eutectoid microconstituent, the thermal conductivity of the composite was varied from 22.8 W m −1  K −1 down to 8.3 W m −1  K −1 . We analyze the thermal conductivity in terms of a series thermal resistance model, including thermal boundary conductances at the heterointerfaces, and show that the thermal boundary conductance is reduced by at least an order of magnitude when the diamond cubic microconstituent is enriched from 0 to 30 at% Ge. Avenues for additional microstructural improvements towards thermoelectric applications are discussed. [ABSTRACT FROM AUTHOR]

Fe-Si alloys ranging from 3 to 8 wt% Si were rapidly solidified using melt spinning. Wheel speeds of 30 m/s and 40 m/s were employed to vary cooling rates. Mössbauer spectroscopic studies indicated the Si content significantly influenced the number of Fe sites, relative abundance of various Fe species, and internal magnetic fields/structural environments. Wheel speed altered Fe speciation only in the 3 wt% sample. Scanning electron microscopy confirmed that increasing the wheel speed refined both the ribbon thickness and grain size. Electron backscatter diffraction results suggest tailoring melt spinning process parameters and alloy chemistry may offer the ability to manipulate {001} texture development. Electrical resistivity measurements were observed to increase in response to elevated Si content. Increased hardness was correlated to elevated Si content and wheel speed. [ABSTRACT FROM AUTHOR]

We carried out sound velocity and density measurements on solid hcp-Fe and an hcp-Fe–Si alloy with 9 wt.% Si at 300 K up to ∼170 and ∼140 GPa, respectively. The results allow us to assess the density ( ρ ) dependence of the compressional sound velocity ( V P ) and of the shear sound velocity ( V S ) for pure Fe and the Fe–Si alloy. The established V P – ρ and V S – ρ relations are used to address the effect of Si on the velocities in the Fe–FeSi system in the range of Si concentrations 0 to 9 wt.% applicable to the Earth's core. Assuming an ideal linear mixing model, velocities vary with respect to those of pure Fe by ∼ + 80 m / s for V P and ∼ − 80 m / s for V S for each wt.% of Si at the inner core density of 13 000 kg/m 3 . The possible presence of Si in the inner core and the quantification of its amount strongly depend on anharmonic effects at high temperature and on actual core temperature. [ABSTRACT FROM AUTHOR]

The present paper reports the effect of sintering temperature on the properties of Fe–SiC metal matrix nanocomposites (5 wt% SiC; 95 wt% Fe) prepared by powder metallurgy technique. Samples were synthesized by ball milling followed by compaction and then sintering in the temperature interval of 900 – 1100℃ for 3 h, respectively. X-ray diffraction, microstructure, density, hardness, wear and corrosion of prepared samples have been investigated. X-ray diffraction studies show the presence of iron (Fe) and silicon carbide (SiC) along with the presence of iron silicate (Fe3Si) phase. Iron silicate is formed as a result of reactive sintering between iron and silicon carbide particles. Scanning electron microscopy of the samples shows the dispersion of SiC in the whole Fe matrix. Density, hardness, wear and corrosion characteristics of the samples were investigated which varies for different sintering temperature interval. It is expected that the results of this paper will be helpful in developing metal matrix nanocomposites for various industrial applications. [ABSTRACT FROM AUTHOR]