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The performance of a vibration power generator using a single crystal core of Fe–Ga alloy was compared with that of a generator using a Fe–Ga alloy polycrystal core with a similar Ga concentration. When the generator using the polycrystal core was forcibly vibrated by 1-G acceleration, the vibration frequency dependence of the open-circuit voltage showed a peak with a maximum value of about 0.14 V at the first resonance frequency due to the inverse magnetostrictive effect. On the other hand, the generator using a single crystal core with a direction parallel to the external stress direction exhibited a maximum value of about 0.26 V, about two-times larger than that of the device using the polycrystal core. Consequently, a vibration energy generator using a single crystal core of Fe–Ga alloy has advantages in performance over a generator using a polycrystal core.

Herein, a method has been described to rapidly obtain a semi-quantitative three-dimensional lithium distribution of a lithium-ion battery graphite anode using laser-induced breakdown spectroscopy (LIBS) measurements. LIBS measurements of the graphite anodes with a diameter of 10 mm were performed in an argon atmosphere of 1000 Pa until the depth of 150 μm using the Li emission line of 610.4 nm. The emission intensity was measured for the pitch of 500 μm in plane. Homogeneous and inhomogeneous lithium distributions were observed in the anodes after both charge and charge-discharge processes. The inhomogeneous lithium distribution after the charge process was attributed to the preferentially reacted area in the anode, while that after the charge-discharge process was likely related to the low desolvation reaction rate of lithium ions at the solid electrolyte interphase. These inhomogeneous lithium distributions were consistent with the results from the charge-discharge curves and the lithium ion transfer mechanism. Thus, it was proven that it is possible to acquire a three-dimensional lithium distribution of a graphite anode of a lithium-ion battery by LIBS measurements.

The saturation value of the magnetostriction curve in the [100] direction of a Fe-Ga alloy single crystal was decreased from 226 to 55 ppm by applying the tensile strain of 533 ppm to the measured direction. By magnetic domain observation using a magneto-optic Kerr effect microscope, a complex structure composed of various magnetic domains was observed under zero applied strain. On the other hand, a stripe structure composed of magnetic domains with the magnetization direction in two kinds of magnetic easy directions parallel to the tensile direction, which were separated by straight 180° domain walls, was observed under the tensile strain of 533 ppm. The characteristic magnetic domain structure due to the tensile strain was successfully observed as a cause of the significant decrease of the saturation value of the magnetostriction curve.

Fe-Ga alloys are used for practical magnetostrictive materials. The understanding of mechanical properties under magnetic field is very important for their application to vibration power generation devices. Especially, Poisson’s ratio is one of key parameters because it is strongly related with the volume change of materials. In the study, we investigated actual behavior of Poisson’s ratio due to magnetostriction, instead of just the mechanical one. The sample was cube-oriented Fe-18mol%Ga single crystal disc. Static magnetic fields were applied in various directions parallel to (001). Strain values in various directions were measured by strain gauge and X-ray diffraction. And then, tri-axial strain analysis for single crystal was carried out. Theoretically, Poisson’s ratio due to magnetostriction is known to be 0.5, (volume conservative), value is close to the mechanical one, 0.45. On the other hand, we found that Poisson’s ratio exhibits anisotropic behavior despite the elastic constants are equivalent in [010] and [001]. This phenomenon is attributable to the magnetic domain structure under zero magnetic field. In this presentation, we will discuss this apparent Poisson’s ratio considering the volume strain and magnetostriction comprehensively.

A method to obtain the quantitative lithium distribution of a lithium-ion battery cathode using laser-induced breakdown spectroscopy (LIBS) measurements is proposed. We perform LIBS measurements in a reduced argon atmosphere of 1000 Pa and use a calibration curve obtained by measuring the emission intensities at 610.4 nm of standard samples, whose atomic ratios of lithium to cobalt are 0, 0.10, 0.30, 0.51, 0.62, 0.80, and 0.99. The lithium distributions of cycled cathodes, which contain LiCoO2 as an active material, obtained by this method are relatively consistent with the Co(III) distributions obtained by X-ray absorption spectroscopy (XAS). XAS is the conventional method to quantitatively display the reaction distribution of a cathode material used in a lithium-ion battery. Additionally, LIBS can detect the precipitating decomposition products of the electrolyte, LiF, on the cathode. However, the precision of the lithium ratio using LIBS is not as good as that achieved for the Co(III) ratio obtained using XAS. Therefore, LIBS is suitable to obtain a semi-quantitative lithium distribution in a cathode of a lithium-ion battery through a much simpler procedure than XAS. Furthermore, LIBS has an advantage to detect the decomposition product of the electrolyte using laboratory-scale measurements.

Cross-sectional shape-controlled Fe-Ga alloy crystals for energy harvester applications were grown using the micro pulling down (μ-PD) method. The investigation of material concentrations along the growth direction reveals that a high growth rate of 5.0 mm/min raises the effective segregation coefficient of Ga, k eff (Ga), and ensures high concentration homogeneity. However, the high growth rate was speculated as causing non-preferentially oriented portion formation that decreases the magnetostrictive property. The magnetostriction 3/2λ = 286 ppm was achieved for a good oriented sample (i.e. the misorientations from 〈100〉 were less than 7.5°.) with the Ga concentration of 16.8 at%. A prototype vibration energy harvester using a plate-shaped Fe-Ga alloy grown at 5.0 mm/min showed comparable or superior performance to the device using commercially available alloys. By leveraging the advantages of near net-shape controlling and a higher growth rate than other crystal growth techniques, the μ-PD method is expected to emerge as a new technique for mass-producing Fe-Ga alloys as materials for energy harvester applications.

We carried out in situ tri-axial magnetostriction analysis for cube-oriented Fe-18%Ga single crystal by X-ray diffraction measurement under magnetic field. Periodic change in tri-axial magnetostriction with applied magnetic field direction was clearly observed. However, those values in [100] and [010] directions were not equivalent. Theoretical calculation of magnetostriction considering domain structure revealed this is caused by the non-equivalent volume fraction of initial magnetic domains.

In this study, in situ white X-ray microbeam diffraction experiments were conducted to investigate the microscopic deformation behavior of a Cu-Al-Mn superelastic alloy during tensile testing. Local deformation both at a grain scale and an intragranular scale was revealed by analyzing Laue spot streaking that occurred within a grain and in some grains with different orientations. The streaking measured within a grain under tensile load showed inhomogeneous behavior because of an inhomogeneous martensitic transformation. Moreover, the effect was dependent on grain orientation. In a grain with a high Schmid factor, a large dispersion in the 2θ diffraction angle of Laue spots was observed due to significant Laue spot streaking, which can be attributed to that grain's favored martensitic transformation.

Fe-Ga alloys show large magnetostriction, which strongly depends on crystal orientation. This phenomenon is associated to some degree with large elastic anisotropy. In this study, white X-ray diffraction with micro-beam synchrotron radiation was used to evaluate the microscopic stresses evolved in a polycrystalline Fe-Ga alloy under tensile loading. In the analysis, the large elastic anisotropy of the Fe-Ga alloy was focused. The stress distribution in the alloy microstructure under tensile loading was estimated using a finite element method (FEM) simulation that considered the dependence of the elasticity on the crystal orientation. The crystal orientation of grains in the polycrystalline Fe-Ga alloy was measured using electron backscatter diffraction. The FEM simulation showed that the stress distribution in the microstructure depended on the crystal orientation. The X-ray diffraction stress analysis indicated that under tensile loading, the stresses in the alloy depended on the crystal orientation. This finding is similar to the results obtained from the FEM simulation, although the absolute values of the stresses may have reflected the effects of heterogeneous deformation on the stress distribution.

The magnetic domain structure on the (0 0 1) plane of an Fe 16.1 Ga 83.9 single crystal grown by the Czochralski method was observed by magneto-optic Kerr effect microscopy. In zero magnetic field, four different domain phases appeared, with magnetization in four kinds of '1 0 0 magnetic easy directions on the (0 0 1) plane. That is, the magnetic domain structure in zero field was composed of straight 90° domain walls and stair-like 180° domain walls. When a magnetic field was applied in the [0 1 0] direction, primarily 180° domain walls moved, whereas 90° domain walls did not. A striped domain structure composed of 90° domain walls was formed at a field of about 560 Oe, 180° domain walls having almost disappeared. A single domain structure was obtained by applying a field of about 1980 Oe. Magnetostriction in the [0 1 0] direction on the (0 0 1) plane was only about 10 ppm in a field of about 560 Oe and reached a saturation value of about 153 ppm at a field of about 1980 Oe. This magnetostrictive behavior contributes to the evolution of the magnetic domain structure.

Single-phase Co carbide particles with the Co 3 C structure were obtained by the polyol process using tetraethylene glycol (TEG) solution containing polyvinylpyrrolidone (PVP). Additionally, particles with a mixture of face-centered cubic Co and hexagonal close-packed Co were precipitated in the TEG solution without PVP. The particles synthesized with PVP exhibited coercivity of about 5.7 kOe, which was larger than that of the particles synthesized without PVP. Thus, the addition of PVP to the TEG solution induces the formation of Co 3 C-structured Co carbide particles with large coercivity. Particles precipitated from the TEG solution with an initial molar ratio of Co:Ni = 8:2 were also identified as the single phase of the Co 3 C structure by X-ray diffraction measurement. In addition, it was confirmed by measurements of the extended X-ray absorption fine structure spectra that Ni atoms in the precipitated particles had a local structure similar to that of Co atoms in the single-phase particles with the Co 3 C structure. Thus, Ni-substituted Co carbide particles with the Co 3 C structure can be obtained by the polyol process using PVP.

Fe-glycolate wires with micrometer-scale lengths can be synthesized by the polyol process. Although the as-produced wires are in the paramagnetic state at room temperature, they are transformed into ferrimagnetic iron oxides and ferromagnetic metallic iron wires by reductive annealing. The shape of the wires is unchanged by reductive annealing, and it is possible to control the magnetic properties of the resulting wire-shaped ferri/ferromagnets by adjusting the annealing conditions. Consequently, the reductive annealing of polyol-derived Fe-glycolate wires is an effective material-processing route for the production of magnetic wires.

The local stress state developed during the elastic deformation of polycrystalline Fe-17mol%Ga was measured by synchrotron white X-ray radiation, and the heterogeneity of the elastic deformation resulting from the pronounced elastic anisotropy of the Fe–Ga alloy system was examined. Tensile loading generated local stresses perpendicular to the tensile direction. The development of these stresses was discussed from the viewpoint of the interaction between grains having different elastic properties.

White X-ray microbeam diffraction was applied to investigate the microscopic deformation behavior of individual grains in a Cu-Al-Mn superelastic alloy. Strain/stresses were measured in situ at different positions in several grains having different orientations during a tensile test. The results indicated inhomogeneous stress distribution, both at the granular and intragranular scale. Strain/stress evolution showed reversible phenomena during the superelastic behavior of the tensile sample, probably because of the reversible martensitic transformation. However, strain recovery of the sample was incomplete due to the residual martensite, which results in the formation of local compressive residual stresses at grain boundary regions.

X-ray diffraction (XRD) and electron microprobe microanalysis (EPMA) were used for characterizing the structure and composition of surface layers formed on austenitic Fe-Mn-Si shape memory alloys under vacuum. The XRD results demonstrated that during annealing, face centered cubic austenite is transformed to hexagonal close packed martensite on the alloy surface. The EMPA results revealed that manganese in the surface layer was depleted during annealing. Further, this analysis determined that the thickness of the surface layer of the alloy annealed at 1173 K for 1 h was approximately 20 μm and that value is consistent with the depth detected by XRD. The compositional changes of the surface layers such as manganese depletion by annealing were discussed based on the ternary Fe-Mn-Si phase diagram. Although the formation of body centered cubic ferrite is detrimental to shape memory alloys, the amount of manganese was also observed to change during processing and strongly influence the stability of the shape memory alloys.

We carried out in situ x-ray diffraction measurements of magnetostriction in an Fe-18at%Ga alloy single crystal under magnetic fields. The sample studied here was a Goss-oriented square plate (dimensions: 10 mm × 10 mm × 1 mm height) cutting from as-grown single crystal ingot produced by the Czochralski method. In-plain magnetic fields were applied with various directions in this study. The influence of magnetic field direction on the stress/strain states was precisely analyzed by using our original x-ray single crystal stress/strain measurement method. As a result, applied field angle dependence of tri-axial magnetostriction states was successfully obtained. Thereby, we found that the singular anisotropic mechanical properties of this material play an important role for its magnetostriction properties.

The magnetic iron oxide particles are very attractive for biomedical applications because of good biological compatibility.

An Fe-Ga alloy single crystal of about 10 mm in diameter and about 60 mm in length was grown by the Czochralski (CZ) method. The as-grown ingot was approximately oriented in the 〈100〉 direction parallel to the pull-up direction. The gallium concentration of the as-grown ingot was close to that of the starting polycrystalline alloy. The magnetostriction of about -212 ppm was observed in the 〈100〉 direction by applying a magnetic field perpendicular to the measured direction. In addition, the superior performance of vibration power generation due to the large inverse magnetostrictive effect was demonstrated by a prototype device using the as-grown Fe-Ga alloy single crystal. It is concluded that Fe-Ga alloy single crystals grown by the CZ method are promising for application to vibration power generators.

Fine crystalline LiFePO 4 particles with an average secondary size of about 200 nm were synthesized in ethylene glycol (EG) solution at 393 K. Their molar ratio of Li:Fe:P was about 1.3:1:1, implying the precipitation of an impurity containing extra Li ions. The unit cell volume of crystalline LiFePO 4 in heat-treated particles was larger than that in as-synthesized particles. The Fe K absorption edge in the X-ray absorption spectrum was shifted toward a lower energy position by heat treatment. These results suggest that the composition of crystalline LiFePO 4 in fine particles is modified by heat treatment because of the reaction with extra Li ions. Additionally, in the radial structural function obtained by Fourier transform of the extended X-ray absorption fine structure oscillation, the Fe–P correlation and Fe–Fe correlation peaks became high due to the heat treatment, implying the rearrangement of FeO 6 octahedra and PO 4 tetrahedra. In consequence of the above-mentioned structural changes, the electronic capacity of fine particles precipitated in EG solution was enhanced to about 150 mA/h by heat treatment at 673 K.

White X-ray diffraction with micro-beam synchrotron radiation was used to analyze microscopic stress evolved in coarse grains of a twinning-induced plasticity Fe-Mn-C steel under tensile loading. In addition, electron backscatter diffraction (EBSD) was used to determine the crystal orientation of grains in the polycrystalline Fe-Mn-C steel. Based on these orientation data, the stress and strain distribution in the microstructure of the steel under tensile loading was estimated using FEM simulation where the elastic anisotropy or the crystal orientation dependence of the elasticity was taken into account. The FEM simulation showed that the strain distribution in the microstructure depends on the crystal orientation of each grain. The stress analysis by the white X-ray diffraction indicated that the direction of the maximum principal stresses at measured points in the steel under tensile loading are mostly oriented toward the tensile direction. This is qualitatively consistent with the results of by the FEM simulation, although absolute values of the principal stresses may contain the effect of heterogeneous plastic deformation on the stress distribution.

The itinerant-electron metamagnetic transition of La(Fe0.88Si0.12)13 becomes indistinct after immersion in distilled-water containing about 8 ppm of the dissolved oxygen (DO) concentration because of aqueous corrosion. However, the aqueous corrosion of La(Fe0.88Si0.12)13 is significantly suppressed by reducing the DO concentration. Thus, isothermal magnetic entropy change after immersion for 30 days in deaerated distilled-water with a DO concentration less than 0.1 ppm is larger than that after immersion for 5 days in distilled-water containing about 8 ppm of the DO concentration. Consequently, the reduction of the DO concentration is effective for preservation of the excellent magnetocaloric effects of La(Fe0.88Si0.12)13 in an aqueous solution, which is a promising heat transfer fluid of room-temperature magnetic refrigeration.

Influence of tungstate ions on the transformation of chloride-containing green rust (GR(Cl − )) to fine goethite (α-FeOOH) particles due to the oxidation reaction via aqueous solution at about 300 K was investigated by in situ measurements of X-ray absorption spectra. Results showed that the transformation rate of GR(Cl − ) in the suspension containing 5 mol% W was lower than that in the suspension without tungstate ions. Almost all tungstate ions in the suspension were adsorbed on GR(Cl − ) and α-FeOOH. It is probable that the adsorption of tungstate ions reduces the transformation rate of GR(Cl − ) and also leads to the precipitation of fine particles.

In situ measurements of X-ray absorption spectra at an Fe K absorption edge were carried out during the transformation of chloride-containing green rust (GR(Cl)) to oxyhydroxide (that is, lepidocrocite (γ FeOOH)), by oxidation via aqueous solution. Results showed that the Fe K absorption edge in X-ray absorption near-edge structure (XANES) spectrum shifted toward the higher energy side with increasing oxidation time. The factor analysis of the XANES spectra, using reference data, implied that dissolution of GR(Cl) and precipitation of γ -FeOOH occur simultaneously. The fraction of γ -FeOOH in the suspension increased continuously with increasing oxidation time, in response to the continuous decrease of the fraction of GR(Cl). The results lead us to conclude that GR(Cl) transforms to γ -FeOOH during oxidation under the present experimental conditions.

The microstructure and magnetic properties of cubic- and tetragonal-La(Fe 1− x Si x ) 13 compounds were systematically investigated. Obtained XRD patterns revealed that a semi-ordered tetragonal-La(Fe 1− x Si x ) 13 phase (termed the τ 2 ′ phase in this work) appears due to quenching from the Si-rich concentration range of the cubic-La(Fe 1− x Si x ) 13 ( τ 1 ) single phase region, whose tetragonality, namely the ratio of short and long axes, is lower than that of the known tetragonal Ce 2 Ni 17 Si 9 -type La(Fe 1− x Si x ) 13 ( τ 2 ) phase. It was also found that the τ 2 ′ phase has not only periodically configurated twin boundaries as a microstructural feature but also unique concentration dependence of magnetic properties, i.e., Curie temperature and spontaneous magnetization drastically decrease with increasing Si concentration.

By annealing at 1323 K, the single-phase formation process of La(Fe0.89Si0.11)13 with a cubic NaZn13-type structure was investigated. A dendritic microstructure composed of an α-Fe phase with a mean size of about 10 μm and a LaFeSi phase in the as-solidified state is completely changed into the NaZn13-type single-phase by annealing for 300 h. The growth of the NaZn13-type phase is steep up to an annealing time ta = 100 h, and then becomes sluggish. As a result, the maximum isothermal magnetic entropy change, Δ S m max , markedly increases with increasing ta up to 100 h in response to the formation of the NaZn13-type phase. In addition, the position of Δ S m max shifts to higher temperature ranges due to the increase of the Curie temperature TC. Accordingly, thorough annealing for the single-phase formation of La(FexSi1−x)13 is important for high-performance magnetic refrigerants.

The ordering process of FePt nanoparticles synthesized in polyol solution at 383 K was investigated. Whereas X-ray diffraction peaks of the as-synthesized specimen corresponded to the fcc structure, the Fe-O correlation and Pt-O correlation peaks were observed in the radial structure functions of Fe and Pt atoms obtained by X-ray absorption spectroscopy. Thus, the as-synthesized specimen was composed of crystalline FePt alloy phase and poorly crystallized Fe- and Pt-oxide phase. In X-ray diffraction patterns of the specimens which were heat-treated at temperatures above 568 K in a mixture of 5%H2 in Ar, diffraction peaks corresponding to superlattice lines were observed. Although the lattice constants of the as-synthesized specimen were much larger than that of the bulk fcc-FePt alloy with equiatomic composition, the lattice constants of the specimen heat-treated at 1173 K were very close to the bulk L10-FePt alloy. Additionally, in the radial structure function, peaks corresponding to the Fe-O and Pt-O correlations disappeared and peaks corresponding to Fe-Pt (or Fe) and Pt-Fe (Pt) correlations clearly appeared after heat treatment at temperatures above 568 K. Consequently, it is highly probable that the disorder-order transformation of FePt nanoparticles synthesized in polyol solution is accompanied by compositional homogenization due to the reduction of the poorly crystallized Fe- and Pt-oxide phase.

Microscopic residual stress evolution in different austenite (γ) grains during shape memory process in an FeMnSiCr alloy was investigated using the white X-ray microbeam diffraction technique. The use of high-energy white X-ray microbeam with small beam size allowed us to measure the microscopic residual stress in coarse γ grains with specific orientation. After tensile deformation large compressive residual stress was evolved in γ grains due to the formation of stress-induced e martensite, but upon recovery heating it almost disappeared as a result of reverse transformation of martensite. The magnitude of compressive residual stress was higher in grains with orientations close to 〈144〉 and 〈233〉 orientations than in a grain with near 〈001〉 orientation. Analysis of the microstructure of each grain using electron backscattering diffraction suggested that the difference in the magnitude of compressive residual stress could be attributed to different martensitic transformation characteristics in the grains.

Fe-Ga alloys are gathering much attention because of good machinability and superior magnetostrictive property for application to actuators and vibration energy harvesters. Recently, Fe-Ga alloy single crystals were successfully grown by the Czochralski (CZ) method [1]. In this study, the relationship between the magnetostrictive property and magnetic domain structure in an Fe-16 at%Ga alloy single crystal grown by the CZ method was investigated. To evaluate the magnetostrictive property, a strain gauge was attached on the (001) plane in the [100] direction. The magnetic domain structure on the (001) plane was observed by a magneto-optic Kerr effect microscope. In the mentioned-above experiments, magnetic fields were applied in the [100] direction on the plane. Figure 1 shows the magnetostriction curve of the specimen. The magnetostriction rapidly increases in the vicinity of 1250 Oe with increasing magnetic field and reaches the saturation value of about 109 ppm at about 2000 Oe. As shown in Fig. 2, 90° domain walls are aligned with the direction at zero magnetic field. Additionally, 180° domain walls form a staircase-like structure. When a magnetic field was applied along the [100] direction, 180° domain walls primarily moved, and they almost disappeared at about 1100 Oe. In other words, a striped domain structure composed of 90° domain walls was observed. The single domain structure was obtained after motion of 90° domain walls under the magnetic field above about 2000 Oe. Therefore, the mentioned-above change of magnetic domain structure corresponds to the magnetostrictive property. It is clear that 180° domain walls easily moved compared to 90° domain walls by applying the magnetic field in the Fe-16 at%Ga alloy single crystal.

The metastable cobalt carbide with the Fe 3 C-type structure (Pnma) has attached much attention as a promising candidate for application to rare-earth free permanent magnets, because large magnetoanisotropy of Co3c has been predicted by the first-principal calculation [1]. The particles of Fe 3 C-type cobalt carbide have been synthesized by reduction of cobalt ions in polyol solution [2]. In this study, particles were synthesized at about 563 K for 30 min in tetraethyleneglycol (TEG) using chemicals such as Co acetate tetrahydrate, Ni acetate tetrahydrate and polyvinylpyrrolidone (PVP). The influence of both PVP and coexisting Ni ions on the precipitation of Fe 3 C-type cobalt carbide particles in polyol solution was examined. Figure 1 shows X-ray diffraction patterns of particles synthesized with and without PVP. When Co ions are reduced in solution without PVP, particles composed of fcc and hcp structures are precipitated. On the other hand, the diffraction peaks of particles synthesized in solution containing PVP are assigned primarily as the Fe 3 C-type structure. Therefore, the presence of PVP in TEG solution accelerates the formation of Fe 3 C-type cobalt carbide. The carbide particles exhibited a coercivity of about 1.7 kOe at room temperature. As shown in Fig. 1, particles synthesized in solution with the initial molar ratio of Co:Ni = 9:1 are also identified as the Fe 3 C-type structure. Their local structure around Ni atoms was investigated by a extended X-ray absorption fine structure (EXAFS) spectrum measurement. The result is shown in Fig. 2(a). The shape of EXAFS spectrum of particles synthesized in solution containing Ni ions is similar to that of Co K edge of Fe 3 C-type cobalt carbide particles as indicated in Fig. 2(b). Consequently, particles of Ni-substituted cobalt carbide with the Fe 3 C-type structure are obtained by controlling reduction conditions.

A novel process for preparing scorodite particles with a diameter of approximately 20 µm from Fe(II) and As(V) in aqueous solution has been developed by DOWA Metals and Mining. In the present study, the dissolution characteristics of iron and arsenic from the scorodite particles synthesized by this process have been investigated under different conditions. The results show that the concentration of arsenic dissolved from the particles in aqueous solution is very low, but it has a complicated dependence on the temperature and pH of the solution. Transmission electron microscopy (TEM) with an energy dispersive X-ray spectrometer (EDS) was used to analyze the morphology, structure, and composition of the scorodite particles. The results indicate that the scorodite particles exhibit a nearly octahedral shape with planes composed of almost (111) planes in the orthorhombic structure. The concentration of iron at the surface of the particles is higher than that of iron inside of the particles. This characteristic morphology, along with the minimal surface defects of the scorodite particles, is considered to be responsible for the low dissolution of arsenic from the particles in aqueous solution. Atmospheric temperature and solution conditions were also found to be important for the safe, long-term storage of arsenic using scorodite particles.

In this Study, Influences of P on the Microstructure, Mechanical Properties, and Retained Austenite Characteristics in Transformation Induced Plasticity (TRIP) Steels Were Investigated. Microstructure of 0.2mass%P Containing TRIP Steel Was Inhomogeneous and it Resulted in Deterioration of the Mechanical Properties. Retained Austenite Characteristics such as Volume Fraction and Carbon Concentration Were Also Affected by P. The Stability of Retained Austenite in P Containing TRIP Steel Was Different from that in P-Free TRIP Steel. Such Difference in the Stability of Retained Austenite Was Attributed to the Effect of the Carbon Concentration in Retained Austenite as Well as their Different Microstructure.

Nanoparticles of Ni carbide of about 50nm in diameter were synthesized by the reduction of Ni salt in a polyol solution in the presence of polyvinylpyrrolidone (PVP). It was found that the aggregation of nanoparticles was suppressed when PVP was added to the polyol solution during synthesis. Diffraction peaks of the fcc and hexagonal structures were observed for the specimen synthesized without PVP. On the other hand, no peaks assigned to the fcc structure and no spontaneous magnetization were observed for the specimen synthesized with 50g/L PVP, although pure bulk Ni are fcc structure and ferromagnetic at room temperature. Additionally, small peaks were observed in the X-ray diffraction pattern at 2a = 26.2, 35.7 and 47.8°, originated not from the impurity phase but from the hexagonal phase. The specimen synthesized with 50g/L PVP was fundamentally identified as Ni carbide with a Ni3C-type structure, as small peaks mentioned above were assigned to superlattice peaks. The structure parameters of the Ni carbide were refined by Rietveld analysis. It is concluded that the formation of the Ni carbide nanoparticles with Ni3C-type structure in the polyol solution is enhanced by the addition of PVP. [doi:10.2320/matertrans.M2012160]