Synchrotron X-ray Diffraction Techniques Research Articles

Measurement methods for surface oxides on SUS 316L in simulated light water reactor coolant environments using synchrotron XRD and XRF

Synchrotron X-ray diffraction (XRD) and X-ray fluorescent (XRF) measurement techniques have been used for non-destructive characterization of surface oxide films on Type 316L austenitic stainless steels that were exposed to simulated primary water environments of pressurized water reactors (PWR) and boiling water reactors (BWR). The layer structures of the surface spinel oxides were revealed ex situ after oxidation by measurements made as a function of depth. The layer structure of spinel oxides formed in simulated PWR primary water should normally be different from that formed in simulated BWR water. After oxidation in the simulated BWR environment, the spinel oxide was observed to contain NiFe2O4 at shallow depths, and FeCr2O4 and Fe3O4 at deeper depths. By contrast, after oxidation in the simulated PWR primary water environment, a Fe3O4 type spinel was observed near the surface and FeCr2O4 type spinel near the interface with the metal substrate. Furthermore, by in situ measurements during oxidation in the simulated BWR environment, it was also demonstrated that the ratio between spinel and hematite Fe2O3 can be changed depending on the water condition such as BWR normal water chemistry or BWR hydrogen water chemistry.

Mixed-layered structure formation during trans-vacant Al-rich illite partial dehydroxylation

The <1 μm fraction of a trans-vacant 1M illite (RM30) was studied by conventional and synchrotron X-ray diffraction (XRD) techniques, combined with thermogravimetric (TG, DTG) methods to investigate the structural transformation of illite at different temperatures and degrees of dehydroxylation (DT). The oriented specimens preheated at 300 and 680 °C correspond to the non-dehydroxylated (DT = 0) and completely dehydroxylated (DT = 100%) 1 M illite structures. Deviation of the basal reflection positions from rationality, expressed by the coefficient of variation of d(00l) values, progressively increase from 0.05 at DT = 4%, to 0.14 at DT = 51%, and then decrease to 0.06 at DT = 95%. Similarly, for each 00l reflection the full width at half-maximum (FWHM) shows a bell-like evolution with increasing preheating temperature. Both of these features are characteristic for mixed-layered structures.

Single-Crystal Structures of Li+-exchanged Zeolite X (FAU, Si/Al = 1.09) from Aqueous Solution Depends on Ion-exchange Temperatures at 293 and 333 K

Two single crystals of fully dehydrated partially -exchanged zeolite X were prepared by the exchange of Na-X, (Si/Al = 1.09), with using aqueous 0.1 M at 293 (crystal 1) and 333 K(crystal 2), followed by vacuum dehydration at 623 K and Torr for 2 days. Their structures were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group at 100(1) K. Their structures were refined using all intensities to the final error indices (using the 1281 and 883 reflections for which ( > ) = 0.075/0.244 and 0.074/0.223 for crystals 1 and 2, respectively. Their compositions are seen to be -FAU and -FAU, respectively. In crystal 1, 17 ions per unit cell are at site I', 15 another site I', 30 at site II, and the remaining 16 at site III; 2 ions are at site II and the remaining 4 at site III'. In crystal 2, 32 and 30 ions per unit cell fill sites I' and II, respectively, and the remaining 25 at site III'; 2 and 3 ions are found at sites II and III', respectively. The extent of exchange increases slightly with increasing ion exchange temperature from 93% to 95%.

Evidence of nanoscale structural phase separation in large bandwidth La0.2Sr0.8MnO3

We have investigated the structural evolution of La0.2Sr0.8MnO3 using temperature dependent high resolution synchrotron x-ray diffraction technique. In a wide temperature range, La0.2Sr0.8MnO3 reveals nanoscale structural inhomogeneity consisting of cubic and tetragonal phases. The present results suggest that domains of nanometer size of the tetragonal (low temperature) phase start nucleating in the cubic (high temperature) phase even above the Neel temperature (T-N). The tetragonal phase fraction increases substantially below T-N. Detailed analysis suggests that the twinned phase is tetragonal, orbital ordered, and insulating. At temperatures below 170 K, a small amount of the cubic phase is retained. The present results reveal the significance of the connectivity between the nanoscale structural phase separation with the physical properties.

Applications of in situ synchrotron XRD in hydrometallurgy: Literature review and investigation of chalcopyrite dissolution

In situ synchrotron X-ray diffraction (S-XRD) techniques are potentially versatile research tools for advancing the current understanding on dissolution reactions of commercially important minerals. The paper presents a review on the applications of S-XRD to investigate solid phase transformations in aqueous media, with emphasis on reactions relevant to hydrometallurgy, including the dissolution of nickel laterite ores and metal sulfides, such as pyrite (FeS2), bornite (Cu5FeS4) and chalcocite (Cu2S). The results of an in situ synchrotron time-resolved X-ray diffraction (S-TRXRD) study of the dissolution of chalcopyrite (CuFeS2) are also reported. The S-TRXRD measurements were carried out in capillary-based cells containing fine particles by using two different experimental approaches — flow method (FM) and non-flow method (NFM). At 25°C (FM), no transformation of the crystal structure was observed, in agreement with the well-known slow dissolution rate of the mineral. In the temperature range 100–200°C (NFM), the formation of covellite (CuS), elemental sulfur (S8), and metal sulfates (ferrous or cupric sulfates) was detected on CuFeS2 particles. Our results demonstrate that the mineral conversion to such product phases commenced about 10min after the start of measurements, and suggested that the formation of elemental sulfur is possibly related to an initial oxidation of CuFeS2 by Fe3+ ions, followed by CuS oxidation by the same oxidants. The new results in combination with the previous reports demonstrate that the S-XRD techniques can be used to improve our knowledge on key hydrometallurgical processes. This work highlights the features of different experimental set-ups and the possibilities to be explored by applying in situ methods, alone or in combination with other analytical tools.

In-situ high-energy synchrotron X-ray diffraction study of micromechanical behavior of multiple phases in Ni47Ti44Nb9 shape memory alloy

High-energy synchrotron X-ray diffraction technique was used to in-situ characterize microstructure, lattice strain, and phase transition behavior of a Ni47Ti44Nb9 shape memory alloy. Phase transformation kinetics and deformation mechanisms were studied under a uniaxial tension at three testing temperatures, i.e., −70°C, 25°C, and 150°C. At a testing temperature of −70°C, a complicated phase transformation with four stages of micromechanical deformation was identified which is associated with changes of martensite substructures. At room temperature of 25°C, there was no stress-induced selection process of variants of B19′ phases observed. Whereas at a testing temperature of 150°C, there was no any phase transformation observed. It is verified that β-Nb phase, an effective stabilizer for the austenite, delays the process of martensitic transformation and relaxes the strain energy without strengthening the matrix. This new finding is important to understand the relationship between the micromechanical deformation behavior and phase transformations in the Ni47Ti44Nb9 SMA.

Competitive molecular interaction among paeonol-loaded liposomes: Differential scanning calorimetry and synchrotron X-ray diffraction studies

Thermotropic phase behavior of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes containing 5 mol% cholesterol, or 5 mol% stigmasterol, or 5 mol% paeonol have been investigated by differential scanning calorimetry (DSC) and synchrotron X-ray diffraction (XRD) techniques, to investigate the competitive molecular interaction among paeonol-loaded liposomes. The results show that both sterol and paeonol can incorporate into hydrophobic region and interact with acyl chains of DPPC. Both 5 mol% sterols and 5 mol% paeonol can promote the formation of rippled gel phase of DPPC liposomes at room temperature. 5 mol% paeonol can induce the occurrence of phase separation in DPPC liposomes, but 5 mol% cholesterol or 5 mol% stigmasterol cannot induce this phenomenon. Both the repeat distance and the correlation length of paeonol-poor domain are larger than those of coexisted paeonol-rich domain. Both calorimetric data and SAXS patterns show that sterols have more favorable, stabilizing interactions with DPPC than paeonol, implying that high concentrations of sterols will have a negative effect on the loading of paeonol. In addition, calorimetric data show that cholesterol have a little more favorable, stabilizing interactions with DPPC than stigmasterol. The results of this study will play an important role in optimizing the formulation of paeonol-loaded liposomes.

Two types of adjacent dimer layers in the low-temperature phase of BaCuSi2O6

The low-temperature crystal structure of ${\mathrm{BaCuSi}}_{2}{\mathrm{O}}_{6}$ has been investigated with high-resolution synchrotron x-ray and neutron powder diffraction techniques and has been found to be on average (ignoring the incommensurate modulation) orthorhombic, with the most probable space group $Ibam$. The Cu-Cu dimers in this material are forming two types of layers with distinctly different interatomic distances. Subtle changes also modify the partially frustrated interlayer Cu-Cu exchange paths. The present results corroborate the interpretation of low-temperature nuclear magnetic resonance and inelastic neutron scattering data in terms of distinct dimer layers.

In-situ synchrotron X-ray diffraction study on the dehydrogenation behavior of NaAlH4 modified by multi-walled carbon nanotubes

The effect of multi-walled carbon nanotubes (MWCNTs) addition on the dehydrogenation behavior of NaAlH4 (sodium alanate) is investigated using high-pressure thermal gravimetric analysis (HPTGA) and in-situ synchrotron X-ray diffraction (in-situ synchrotron XRD) technique. The HPTGA results show that the addition of MWCNTs facilitates dehydrogenation of NaAlH4 by lowering the first-step dehydrogenation temperature to 80 °C. In-situ synchrotron XRD analysis demonstrates that the dehydrogenation pathway can be modified by the addition of MWCNTs which resulting in an enhanced hydrogen desorption rate and reduced desorption temperature.

Single-Crystal Structures of Fully and Partially Dehydrated Zeolite Y (FAU, Si/Al = 1.56) Ni2+ Exchanged at a Low pH, 4.9

The crystal structures of zeolite Y Ni2+ exchanged at pH 4.9, fully dehydrated (|Ni29.7(Ni4AlO4)1.1H12.3|[Si117Al75O384]-FAU) and partially dehydrated (|Ni14.1(NiOH2)16.4(Ni4AlO4)1.1(H3O)9.6|[Si117Al75O384]-FAU), were determined by single-crystal synchrotron X-ray diffraction techniques. They were refined to the final error indices R1/wR2 = 0.044/0.115 and 0.052/0.153, respectively, in the cubic space group Fd3m. Some dealumination of the zeolite framework occurred during Ni2+ exchange. In the fully dehydrated structure, Ni2+ ions primarily occupy sites I and II, with additional Ni2+ ions at site I′, site II′, and a second site II. In the partially dehydrated structure, Ni2+ occupies six different sites: I, I′, a second site I′, II, a second site II, and III′. Because of the low pH of the Ni2+ exchange solution, some H3O+ ions are observed in partially dehydrated Ni2+–Y; correspondingly, some H+ ions are required for charge balance in fully dehydrated Ni2+–Y. The nonframework oxygen atoms in water and or...

Red soil chemistry and mineralogy reflect uniform weathering environments in fluvial sediments, Taiwan

Information on the physicochemical properties, mineral species and micromorphology of lateritic soils and gravel soil layers in paleo-environmental soil profile is severely lacking. Red soil profile of the Taoyuan terrace was employed to demonstrate its different extents of lateritic weathering. The objectives of this study were to compare the physicochemical properties of lateritic soils and gravel soil layers and identify using conventional and synchrotron X-ray diffraction (XRD) analyses mineral species in nanoparticles separated by automated ultrafiltration device (AUD) apparatus. Soil samples were collected from paleo-environmental lateritic soils. Soil samples were examined using elemental analysis, conventional and synchrotron XRD analyses, high gradient magnetic separation, separation and collection of nanoparticles by AUD apparatus, and transmission electron microscopy (TEM). The soil pH, redness index, quantities of free Al- and Fe-oxides (Ald and Fed), and clay content of lateritic soils are higher than those of gravel soil layers. Illite, kaolinite, gibbsite, quartz, goethite, and hematite were identified in clay fractions and nanoparticles by conventional and synchrotron XRD analyses. TEM images show presence of hematite nanoparticles on the surface coating of kaolinite nanoparticles and aggregated hematite nanoparticles overlapping the edge of a kaolinite flake in a size range of 4–7 nm. Synchrotron XRD techniques are more straightforward and powerful than conventional XRD with random powder methods for identifying nanoparticles in red soils, particularly for illite, kaolinite, goethite, and hematite nanoparticles. According to chemical compositions of clay fractions and red soil features in the Taoyuan terrace, these red soils can be taken as lateritic red earths or red earths. This work suggests that physicochemical properties, mineral species, and micromorphology of red soil at all depths can shed light on the extent of paleo-environmental lateritic weathering.

Deformation modes of nanostructured thin film under controlled biaxial deformation

This paper reports on the mechanical behaviour of nanostructured W/Cu thin films deposited on Kapton® under controlled biaxial loadings thanks to a biaxial testing device developed on DiffAbs beamline at SOLEIL synchrotron (Saint-Aubin, France). In situ tensile tests were carried out combining 2D synchrotron X-ray diffraction (XRD) and digital-image correlation (DIC) techniques. First, the elastic behaviour of the composite metallic film — polymeric substrate was investigated under equi-biaxial and non-equi-biaxial loading conditions. The results show that the strain measurements (in the crystalline film by XRD and the substrate by DIC) match within 10−4. This result demonstrates the full transmission of strains in the elastic domain through the film-substrate interface and thus a good adhesion of the thin film to the substrate. The second part of the paper deals with higher strains response under equi-biaxial tensile tests. The elastic limit of the nanostructured W/Cu thin films was determined at the bifurcation point between strains obtained by XRD and DIC. Deformation mechanisms such as strain localisation and film fragmentation are proposed.

In-situ synchrotron X-ray diffraction study of stress-induced phase transformation in Ti50.1Ni40.8Cu9.1 thin films

Stress-induced martensitic transformation of as-sputtered and post-annealed Ti50.1Ni40.8Cu9.1 thin films was investigated using in-situ synchrotron X-ray diffraction (S-XRD) technique. For the as-deposited film, in-situ S-XRD analysis showed a martensitic transformation from parent phase to martensite during initial loading, followed by reorientation of martensite variants via detwinning. This detwinning process induced a strong 〈020〉 fiber texture along the loading direction and a strong 〈002〉 fiber texture perpendicular to the loading direction. For the 650°C annealed film, there is only elastic deformation, followed by a martensitic transformation during deformation.

Li+ Exchange into Zeolite Na–Y (FAU) from Aqueous Methanol. Single-Crystal Structures of Fully Dehydrated Li,Na–Y

The ion exchange of Li+ into zeolite Na–Y, |Na75|[Si117Al75O384]-FAU, was attempted using methanol–water mixed solvents. Four solvents ranging in composition from as-purchased (undried) methanol (water concentration 0.02 M) to pure water were used. Four single crystals of Na–Y were treated with 0.1 M LiNO3 in each of the four solvents at 333 K, followed by vacuum dehydration at 673 K. Their structures were determined by single-crystal synchrotron X-ray diffraction techniques at 100(1) K in the space group Fd3m. In the four structures, Li+ and Na+ fill sites I′ and II; the remaining cations, when they can be found, occupy III′ sites. The site preference for Li+ over Na+ is approximately I′ > II > III′. The greatest degree of exchange of Li+ for Na+, 96%, was achieved from undried methanol under the conditions employed. The extent of Li+ exchange decreases with increasing water content and was least, 72%, from pure water. The low water content of the undried methanol appears to play an essential role in th...

Hollow Iron Oxide Nanoparticles for Application in Lithium Ion Batteries

Material design in terms of their morphologies other than solid nanoparticles can lead to more advanced properties. At the example of iron oxide, we explored the electrochemical properties of hollow nanoparticles with an application as a cathode and anode. Such nanoparticles contain very high concentration of cation vacancies that can be efficiently utilized for reversible Li ion intercalation without structural change. Cycling in high voltage range results in high capacity (∼132 mAh/g at 2.5 V), 99.7% Coulombic efficiency, superior rate performance (133 mAh/g at 3000 mA/g) and excellent stability (no fading at fast rate during more than 500 cycles). Cation vacancies in hollow iron oxide nanoparticles are also found to be responsible for the enhanced capacity in the conversion reactions. We monitored in situ structural transformation of hollow iron oxide nanoparticles by synchrotron X-ray absorption and diffraction techniques that provided us clear understanding of the lithium intercalation processes during electrochemical cycling.

Effect of laser shock peening on residual stress and fatigue life of clad 2024 aluminium sheet containing scribe defects

Laser peening at a range of power densities has been applied to 2-mm-thick sheets of 2024 T351 aluminium. The induced residual stress field was measured using incremental hole drilling and synchrotron X-ray diffraction techniques. Fatigue samples were subjected to identical laser peening treatments followed by scribing at the peen location to introduce stress concentrations, after which they were fatigue tested. The residual stresses were found to be non-biaxial: orthogonal to the peen line they were tensile at the surface, moving into the desired compression with increased depth. Regions of peen spot overlap were associated with large compression strains; the centre of the peen spot remaining tensile. Fatigue lives showed moderate improvement over the life of unpeened samples for 50 μm deep scribes, and slight improvement for samples with 150 μm scribes. Use of the residual stress intensity Kresid approach to calculate fatigue life improvement arising from peening was unsuccessful at predicting the relative effects of the different peening treatments. Possible reasons for this are explored.

Effect of High Pressure on the Typical Supramolecular Structure of Guanidinium Methanesulfonate

We report the high-pressure response of guanidinium methanesulfonate (C(NH(2))(3)(+)·CH(3)SO(3)(-), GMS) using in situ Raman spectroscopy and synchrotron X-ray diffraction (XRD) techniques up to the pressures of ~11 GPa. GMS exhibits the representative supramolecular structure of two-dimensional (2D) hydrogen-bonded bilayered motifs under ambient conditions. On the basis of the experimental results, two phase transitions were identified at 0.6 and 1.5 GPa, respectively. The first phase transition, which shows the reconstructive feature, is ascribed to the rearrangements of hydrogen-bonded networks, resulting in the symmetry transformation from C2/m to Pnma. The second one proves to be associated with local distortions of methyl groups, accompanied by the symmetry transformation from Pnma to Pna2(1). The cooperativity of hydrogen bonding, electrostatic, and van der Waals interactions, as well as mechanisms for the phase transitions is discussed by means of the local nature of the structure.

Crystallographic Verification that Copper(II) Coordinates to Four of the Oxygen Atoms of Zeolite 6-Rings. Two Single-Crystal Structures of Fully Dehydrated, Largely Cu2+-Exchanged Zeolite Y (FAU, Si/Al = 1.56)

Two single crystals of fully dehydrated, mostly Cu2+-exchanged zeolite Y were prepared by the exchange of Na75–Y (|Na75|[Si117Al75O384]-FAU, Si/Al = 1.56) with an aqueous stream 0.05 M in Cu(NO3)2, pH = 4.2, at 294 K for 18 and 24 h, respectively, followed by vacuum dehydration at 673 K and 1 × 10–6 Torr. Their crystal structures were determined by synchrotron X-ray diffraction techniques in the cubic space group Fd3m at 100(1) K and were refined to the final error indices R1/wR2 = 0.050/0.165 and 0.050/0.163, respectively, for |Cu32.6Na5.3H4.5|[Si117Al75O384]-FAU and |Cu33.0Na3.9H5.1|[Si117Al75O384]-FAU, respectively. Cu2+ ions occupy the 6-ring sites I′ and II, preferring I′; Na+ ions also occupy sites I′ and II; neither site is filled. All Cu2+ ions in these structures coordinate not only to three trigonally arranged oxygen atoms of their 6-rings, but also to a fourth oxygen atom of those 6-rings to achieve planar, severely distorted square, 4-coordination. This result is in agreement with DFT calcula...

C–H Bond Activation by Pd-substituted CeO2: Substituted Ions versus Reduced Species

Substituted metal oxides containing ionic species have been attracting a great deal of attention because of their potential ability to reduce the usage of precious metals in heterogeneous catalysts. We investigate Pd-substituted CeO2 for C–H bond activation reactions including the partial oxidation and dry reforming of CH4. This catalyst has been previously studied for CO oxidation, NOx reduction, and the water-gas shift reaction. Pd-substituted CeO2, Ce1–xPdxO2−δ, was prepared as a powder with high surface area and a hollow sphere morphology using ultrasonic spray pyrolysis. The catalysts were extensively characterized using synchrotron X-ray diffraction and other techniques, confirming phase pure samples up to 10 mol % Pd substitution. Ce0.95Pd0.05O2−δ was found to be active for partial oxidation of CH4 around 500 °C and higher. Our studies, including postcatalytic synchrotron diffraction, suggest that the single-phase Ce1–xPdxO2−δ material is not the active species and that catalysis occurs instead over the reduced two-phase Pd0/CeO2. This observation has been further confirmed by verifying the activity of the reduced Pd0/CeO2 catalysts for ethylene hydrogenation, a reaction that is known to require Pd0.

Single-Crystal Structure of a Toluene Sorption Complex of Fully Dehydrated, Fully Mn2+-Exchanged Zeolite Y (FAU), |Mn37.5(C7H8)17|[Si117Al75O384]-FAU

A single crystal of zeolite Y, 0.30 mm in diameter, fully exchanged with Mn2+ and fully dehydrated, was treated with zeolitically dry toluene at 298(1) K and a pressure of 1.3 × 10–4 Pa and evacuated for 2 h. The crystal structure, |Mn37.5(C7H8)17|[Si117Al75O384]-FAU (a = 24.5923(1) Å), was determined by synchrotron X-ray diffraction techniques in the space group Fd3̅m at 100(1) K and was refined to the final error indices R1 = 0.083 and wR2= 0.230. Mn2+ ions occupy sites I, I′, II′, and II with occupancies at 14, 4, 2.5, and 17, respectively. The 17 Mn2+ ions per unit cell at site II each coordinates to three framework oxygen atoms at 2.213(6) Å and extends into the supercage by 0.63 Å from their plane. Each of these Mn2+ ions also interacts facially with a toluene molecule (Mn2+–toluene center = 2.62 Å). The methyl group is somewhat off the plane of the ring, indicative of a net repulsive interaction with the zeolite framework.