Varying Fe Content Research Articles

Effect of process parameters and coating microstructure on powdering behaviour of galvannealed steel sheets

Formability of galvannealed sheets (GA) is an important feature in the automobile market. Various studies have been conducted on the formability of galvannealed steel sheets and it is known that the powdering property of the galvannealed coating is extremely sensitive to its gamma phase present in the coating and variations in Fe content in the coatings. The present work has been carried out to determine the powdering behaviour of GA product and to obtain correlations between the coating microstructure with powdering behaviour. Powdering of IF–HS–GA is more sensitive than IF–GA in terms of line speed conditions. Iron content (above 10%) of the coating has influence on the powdering behaviour of the steel. This paper also shows correlations between powdering and process parameters.

Magnetic Properties and Crystallographic Structure of Fe$_{3}$Pt Thin Films

Fe100-xPtx (x = 20, 25, and 30) thin films with nominal thickness 50 nm were prepared by radio-frequency (RF) magnetron sputtering onto glass substrates. Crystallographic structure and magnetic properties of such films were investigated by varying Fe content, annealing temperature (400-700degC), and heating process. Crystallographic structure obtained by X-ray diffraction (XRD) indicated that ordering of L12 Fe3Pt phase takes place for Fe75Pt25 postannealed above 400degC. Ordering parameter of the Fe75Pt25 sample increases from 0.29 to 0.94 as annealing temperature rises from 400degC to 700degC. Saturation magnetization 1270 emu/cm3 was obtained in Fe75Pt25 films annealed at 700degC. Fe70Pt30 films annealed at 700degC show similar characteristics with those of Fe75Pt25, while Fe80Pt20 films exhibit paramagnetism due to disordered Fe-rich face-centered cubic (fcc) structure. Postannealing seems necessary for formation of pure L12 Fe3Pt phase while in situ annealing leads to formation of a metastable tetragonal Fe3Pt phase, as confirmed by XRD.

Systematic biotic responses to palaeoenvironmental change in the Late Pleistocene southern South China Sea: a preliminary study

AbstractOxygen and carbon isotopes from the planktonic foraminifer Globigerinoides sacculifer, trace element contents, calcium carbonate, biogenic silica, grain size, and abundances of diatoms, radiolarians and foraminifera in a deep‐sea core from the southwestern South China Sea were analysed to investigate the response of various marine ecological communities to environmental changes over the last 200 ka. The synthesised results show that the quality of the palaeoecological environment for biological growth is primarily affected by nutrient supply and terrigenous disturbance. Ba and P are important nutrient elements for the growth of diatoms, radiolarians and planktonic foraminifera. Together with dissolved silica and calcium carbonate in sea water, these elements may control microbiotic development. However, variations in Fe content appear to affect diatom and radiolarian abundance. Optimal biotic growth occurs when nutrients are abundant and when there is minimal terrigenous disturbance. Biotic growth decreases when sea water is highly oligotrophic and terrigenous input is high. Maximum biological growth occurred in the mid Holocene, but deteriorated soon afterwards owing to increased terrigenous input, causing a decrease of biological abundance and productivity in the late Holocene. The results also indicate how the Toba volcanic eruption ca. 74 ka ago contributed to changing the ecological environment in the southern South China Sea. Copyright © 2008 John Wiley & Sons, Ltd.

Microstructure- and property-controllable NdAlNiCuFe alloys by varying Fe content

We report the formation of microstructure- and property-controllable Nd60Al10Ni10Cu20−xFex (0 ≤ x ≤ 20) alloys by varying the content of Fe element. The microstructure of the Nd-based alloy can be changed progressively from a full glassy state into a composite state with nanocrystalline particles in the glassy matrix and, finally, into a nanostructured state, accompanied by variation in magnetic property gradually from paramagnetic to hard magnetic. The role of Fe addition in the control of microstructure and magnetic property is clarified. We expect that the results would have implication in the development of the microstructure- and property-controllable functional materials for various applications.

Photocatalytic behaviors and structural characterization of nanocrystalline Fe-doped TiO2 synthesized by mechanical alloying

Nanocrystalline Fe-doped TiO2 powders were synthesized by mechanical alloying (MA) with varying Fe contents from 0 up to 4.8wt.% to shift the absorption threshold into the visible light region. The photocatalytic feasibility of the Fe-doped TiO2 powder was evaluated by quantifying the visible light absorption capacity using ultraviolet and visible (UV-Vis) spectroscopy and photoluminescence spectroscopy. Effects of Fe additions on the crystal structures and the morphologies of the Fe-doped powders were also investigated as a function of the doping content using transmission electron microscopy–electron diffraction pattern (TEM–EDP), X-ray diffraction (XRD) and energy dispersive X-ray (EDAX) and X-ray photoelectron spectroscopy (XPS). The UV-Vis study showed that the UV absorption for the Fe-doped powder moved to a longer wavelength (red shift) and the photoefficiency was enhanced. Based on the analysis of the photoluminescence spectra, the red shift was believed to be induced by localizing the dopant level near the valence band of TiO2. The UV-Vis absorption depended on the Fe concentration. TEM–EDP and XRD investigations showed that the Fe-doped powder had a rutile phase in which the added Fe atoms were dissolved. The rutile phase was composed of spherical particles and chestnut bur shaped particles, resulting in a larger surface area than the spherical P-25 powder.

Small-angle neutron scattering measurements with polarised neutrons on Fe–Ag magnetic granular systems

Different Fe-Ag magnetic granular samples have been prepared by changing the relative Fe volume concentration. The evolution of their morphology with iron concentration has been studied by small angle scattering measurements performed with polarised neutrons. The particles average size determined from nuclear scattering data is about 7 Å and it does not change with varying Fe content. On the other hand, the shapes of nuclear and magnetic scattering curves are different in the range of sizes corresponding to magnetic particles, indicating that similar structures display different magnetic behaviours. Finally, the analysis of polarised neutron data suggests the existence of Fe rich regions with negligible magnetisation.

Crystal growth and superconductivity of Fe-doped YBCO single crystals

Fe-doped YBa 2Cu 3O 7− δ (YBCO or Y123) single crystals have been grown using the SRL-CP crystal pulling technique for possible SNS junction applications. By varying Fe content in the liquid in the range of 0–3.73 mol%, the Cu sites substituted by Fe were found in the range of 0–5.45% and accordingly the k eff (effective Fe distribution coefficient) changed in the range of 0.35–0.75. The Fe interface composition in liquid C i is almost the same as the Fe bulk liquid composition C o, suggesting that interface kinetics is predominant and diffusion factor is negligible from the Fe solute point of view. The increasing substitution of Fe at Cu sites resulted in the decreasing trend of superconducting transition temperature ( T c). It was found that the magnetization of the samples strongly depended on the annealing temperature. The reduction of T c was about 8.6 K/[Fe/(Fe+Cu)]% by annealing at 500°C, whereas about 4 K/[Fe/(Fe+Cu)]% by annealing at 420°C

Hydrothermal (200°C) synthesis and crystal chemistry of iron-rich kaolinites

Abstract:In order to study Al-Fe substitution, Fe-kaolinites were synthesized at 200°C from glasses (Si/(Al + Fe) = 1) with varying Fe content. XRD and IR spectroscopy showed that kaolinites with increasing Fe contents could be synthesized, and Mössbauer spectroscopy indicated that the iron is strictly ferric. Chemical analyses (STEM) of kaolinite particles determined up to almost 7% Fe2O3, which probably does not represent a structural limit. The effect of Fe3+ content is evident on growth kinetics and particle size of kaolinites, both decreasing with % Fe2O3. However, it is not possible to establish a general correlation between Fe content and percentage of structural defects. Acccording to IR spectroscopy, some synthesized Fe-rich kaolinites can have relatively good crystallinity.

Platinum-group elements and gold in the komatiite-hosted Fe-Ni-Cu sulfide deposits at Kambalda, Western Australia

The concentrations of all platinum-group elements and gold in monthly composited samples of mined ores have been determined by neutron activation analysis. Average values from a typical medium Ni tenor ore shoot (10% Ni in 100% sulfides) are: Os, 480; Ir, 230; Ru, 980; Rh, 320; Pt, 1,650; Pd, 2,050; Au, 500 (all values are in ppb and are recalculated to 100% sulfides). These values are similar to those reported from other komatiite-hosted ores. Os, Ir, Ru, Rh, and Pd correlate strongly with Ni (r = 0.63 to 0.92) whereas Pt (r = 0.50) correlation with Ni is only moderate. Au does not correlate with Ni (r = -0.28).Geochemical profiles of platinum-group element values recalculated to 100 percent sulfides through typical ore zones show that Pt, Pd, and Au are lower in massive ore relative to overlying matrix and disseminated ores, whereas other platinum-group elements have a more uniform distribution through these ore types. Pt, Pd, and Au are strongly concentrated at the footwall metabasalt-massive ore contact and in small sulfide-filled fractures within the footwall metabasalt. Other platinum-group elements are concentrated to a lesser extent at this position. Some magnetite-rich selvedges immediately above massive ores are depleted in Os, Ir, and Ru.Pt, Pd, and Au largely occur in discrete mineral phases (Hudson and Donaldson, 1984) and Os, Ir, Ru, and Rh are interpreted to occur in solid solution in pentlandite. The present concentration of Pt, Pd, and Au at the base of massive ores in late fractures is attributed to metamorphic remobilization although this does not preclude an original magmatic concentration of platinum-group elements at the base of the massive ore. The variation in the platinum-group element content of bulk ore samples is similar to that of Ni, Cu, and Co and is controlled by a variation in Fe content at constant sulfur levels.

A Mössbauer study on remarkable changes in chemical states of iron in silica-supported Pd-Fe bimetallic catalysts by varying Fe contents

Fe-57 Mossbauer spectra of silica-supported Pd−Fe bimetallic catalysts show remarkable changes with varying Fe/Pd atomic ratios. From the spectra, the main Fe-component is estimated as highly dispersed Fe in the Fe/Pd range of 0.05–0.3 and α-Fe ensemble and Fe−Pd intermetallics in the Fe/Pd range above 0.3. It is suggested that the chemical state of iron is associated with the catalytic performance in effective CO−H2 conversion to methanol.

Fe content in pyroxenes from a calc-alkalic volcanic suite, New Mexico, U.S.A.

Electron microprobe analyses of clinopyroxene, both phenocrysts and groundmass, in the calc-alkalic suite (basalt-basaltic andesite-andesite-latite) of the Mogollon Plateau, New Mexico, show little variation in Fe content. The clinopyroxene averages approximately Wo 40En 42Fs 18 in composition and does not vary more than about 7 percent Fs content throughout a suite of rocks that range from 50 to 65 percent in SiO 2 content. Orthopyroxene, on the other hand, is restricted to basaltic andesites and andesites and shows slightly greater variation in Fe content than the clinopyroxenes. It is suggested that the factors limiting concentration of Fe in calc-alkalic magmas, such as high oxygen pressures, are reflected in the clinopyroxenes crystallizing in these magmas by their limited range in Fe content.

Quantometric Analysis of High Alloy (1st Report)

Stainless steel is quantometrically analysed by a large spectrometer fitted with a grating of high dispersion.The spectrometer is of the largest type used in quantometers;its dispersion is 3.3A/mm (1st order), yet there was some difficulty in selecting spectral lines.Feussner's spark is used for excitation with a plane-finished sample as the upper electrode and a tungsten rod as the counter electrode.12000 volts as the secondary voltage, 0.0033 micro farads as the capacitance, 20 seconds as the pre-spark time and only the residual inductance were for obtaining suitable excitation.Results are in agreement with those of chemical analysis with errors of less than 1% for Ni and Cr and less than 2% for Si, Mn, Cu and Mo.As the analysis on different kinds of stainless steel is influenced by coexisting elements, parallel working curves are prepared by using standardized samples. The error caused by variation of Fe content is corrected by multiplying set values by a coefficient.