The growth kinetics of Cu2ZnSnS4 thin films and powders was studied using in-situ synchrotron data. Isothermal and isochronal measurements were performed at the MCX beamline of the Elettra synchrotron (Trieste, Italy). Diffraction line profile analysis was used to follow the changes in the domain size distribution during isothermal measurements, and the change in the mean volume of the domains was studied using the Johnson-Mehl-Avrami equation. The growth was found to be diffusion controlled from small dimensions while the nucleation rate is temperature dependent. An activation energy of 210 kJ/mol could be estimated. In case of the isochronal data, the evolution of inverse of the integral breadth of the diffraction peaks in dependence on temperature was studied using the Ozawa and Šatava equations. The activation energy determined for the growth process is between 112(2) and 145(5) kJ/mol.

In order to investigate the hydrogenation of intermetallic compounds, a gas pressure cell for in situ neutron powder diffraction based on a sapphire crystal tube was constructed. By proper orientation of the single crystal Bragg peaks of the container material can be avoided, resulting in a very low diffraction background. Using a laser heating and gas pressure controller, the hydrogenation (deuteration) of palladium and palladium rich intermetallics was studied in real time up to 8 MPa gas pressure and 700 K. Crystal structure parameters of palladium deuterides could be obtained under various deuterium gas pressures, corresponding to compositional ranges of 0.04≤x≤0.11 for the α-phase and 0.52≤x≤0.72 for the β-phase at 446 K. In situ neutron powder diffraction of the deuteration of a thallium lead palladium intermetallic Tl1-xPbxPd3 shows two superstructures of the cubic closest packing (ccp) to transform independently into a AuCu3 type structure. This proves a direct reaction to the deuterium filled AuCu3 type structure instead of a reaction cascade involving different ccp superstructures and thus gives new insights into the reaction pathways of palladium rich intermetallic compounds.

A time-resolved powder diffraction study of the crystallisation of porous metal organic framework materials with the CPO-27 structure ([M2(dhtp)(H2O)2]·8H2O where, dhtp=2,5-dioxoterephthalate) using the energy dispersive X-ray diffraction method is described. Crystallisation under solvothermal conditions is performed between 70 - 110 °C from clear solutions of metal salts (M=Co2+ or Ni2+) and 2,5-dihydroxyterephthalic acid in a mixture of THF-water in sealed reaction vessels, using both conventional and microwave heating. Integration of Bragg peak areas with time provides accurate crystallisation curves, which are modelled using the method of Gualtieri to determine rate constants for nucleation and for growth and then, by Arrhenius analysis, activation energies. Crystallisation is determined to be one-dimensional, consistent with the elongated morphology of the crystals produced in these reactions. With conventional heating the Co-containing CPO-27 crystallises more rapidly than the isostructural Ni-containing analogue and analysis of the kinetic parameters would suggest a complex multi-step crystallisation process. The effect of microwave heating is upon activation energies: the values for both nucleation and for crystal growth are lowered compared to reactions using conventional heating.

Neutron diffraction (ND) was used to investigate the crystallographic preferential orientation (CPO, texture) and structure parameters of four samples of metagabro mylonite collected from the eastern part of the metagabbro sheet at the Stare Mesto belt, Bohemia Massif, Czech Republic. The samples were selected to form a deformation-ordered series with the microstructure varying from non-deformed metagabbro protolith to strongly sheared ultramylonite and amphibole-rich ulramylonite. The specimens used in ND measurements were polished in form of an exact sphere with diameter 50 ± 0.1 mm. The obtained ND patterns were corrected for non-linear background and then evaluated using the Rietveld method implemented in the software package GSAS. Data recorded from powder preparded by milling material from the sampled rocks were used to refine the structure parameters of plagioclase (labradorite structure, triclinic space group C-1) and amphibole (monoclinic space group C2/m). The experiments were performed on the KSN-2 neutron diffractometer situated at the research reactor LVR-15 of the Nuclear Research Institute, plc. Rez, Czech Republic. The data sets of ND patterns measured on each of the four spherical specimens consisted of 90 diagrams collected for different diffraction vectors covering uniformly one orientation hemisphere of the specimen. Based on the collected data, the orientation distribution function (ODF) of crystalline grains was determined by Rietveld harmonic method (coefficients C(l,m,n) of the spherical harmonics expansion determined up to the order L = 8) for the two principal mineral phases - amphibole and plagioclase. The ODF was used to reconstruct (001), (020), (021), (110), (111) (plagioclase) and (001), (11-1), (020), (110), (200) (amphibole) pole figures (PFs). Direct method of ODF calculation implemented in ResMat software package was then used to calculate inverted pole figures (IPFs) of the plagioclase phase. CPO of the amphibole and plagioclase is then discussed in terms of the obtained texture indices and calculated PFs and IPFs and compared with data measured by other methods or available in literature.

This work aims to investigate the hydration behavior and structural properties of two dioctahedral smectites with contrasting location charge (beidellite SbId-1 and montmorillonite SWy-2) according to the nature of the bivalent compensator heavy metal cations (i.e. Hg (II), Ni (II), Ba (II) and Mg (II)). This study is achieved using XRD profile modeling approach based on the simulation of the 00l reflection which allowed us to determine structural characteristics along the c* axis related to the nature, abundance, size, position and organization of exchangeable cation and water molecule in the interlamellar space along the c* axis. The obtained results show that a heterogeneous hydration behavior is systematically observed in all studied samples and the structural models, used to fit samples with tetrahedral charge, are more heterogeneous than smectite with an octahedral sheets substitution. In the case of exchanged beidellite specimen, the proposed models are described by a mixed layer structure with variable abundance containing respectively, dehydrated (0W), mono-hydrated (1W) and bihydrated (2W) layers. Whereas, in the case of the montmorillonite, the absence of 0W hydration state is noted.

To gain accuracy and, hence, physical reality of the data acquired by XRD measurements of fibre textures, a technique is elaborated to achieve experimental values, which are free of extinction effects. Its elaboration is based on combining basic definitions of the extinction theory and texture analysis. This technique is applicable to characterization of metal coatings that appear infinitely thick for X-rays. A nickel sample representing <100> + <221> texture components is used as a model. Resultant derived series of data on pole-density distribution of the {200} diffraction pole figure shows that the data corresponding to the main <100> texture component are strongly affected by extinction. On the contrary, due to definitions that require reduction of the intensity distribution to multiples of random density, the extinction-free values of the volume fraction of texture components do not differ substantially from those calculated by standard methods. Evidently, any of the standard methods for volume fraction measurements provides reasonable data if secondary extinction is even disregarded.

In present investigation, effect of modulation and machining parameters on deformation level of the chips produced during modulation assisted machining (MAM) has been studied. It is shown that disruption in tool-chip contact during modulation assisted machining helps in the formation of discrete chips. Size and shape of the particles produced in MAM can be controlled by varying modulation and machining conditions. Particulates of different shapes and sizes ranging from 100 µm to 5 mm with an aspect ratio of ~10 were produced using MAM. The morphology of the particulates produced was characterized by scanning electron microscope (SEM). Deformation in chip particulates was investigated using X-Ray diffraction. The crystallite size and internal strain in particulates were evaluated using Scherrer and Williamson-Hall methods respectively. The crystallite size of the particulates was found to decrease with decrease in their size, whereas internal strain in particulates was observed to increase with decrease in their size. Furthermore, the length of particulates was observed to decrease with an increase in the ratio of frequency of modulation (fm) to frequency of workpiece rotation (fw). However, the corresponding change in microstrain and crystallite size was insignificant with change in this ratio.

Linear Friction Welding (LFW) has tremendous potential for joining components from similar and dissimilar materials, avoiding material melting and introducing minimal distortion and only moderate levels of residual stress. However, the significant amount of attendant shear introduces preferred crystal orientations that have not yet been well studied. The “one-shot” approach to the interpretation of multi-element energy-dispersive X-ray powder diffraction data allows preferred orientation analysis without any sample preparation (cutting or polishing) or sample rotation. The key step for texture analysis by X-ray powder diffraction is the derivation of the orientation distribution function (ODF) from experimental data. Matlab toolbox “MTEX” provides a powerful function “calcODF” based on the harmonics method for this purpose. In the study reported in this paper, energy dispersive X-ray diffraction patterns were collected using the “horseshoe” multi-element energy-dispersive Ge detector installed on the JEEP beamline at Diamond Light Source. A single exposure was used for each gauge volume of interest, and a line was scanned across an Aluminum 2024 alloy LFW sample. The patterns were converted into raw pole figures through single peak fitting and equal area projection. The ODF calculation was performed based on these pole figures using Matlab toolbox “MTEX”. As a result, full pole figures obtained after ODF calculation were obtained. These are presented and discussed. The results show that the thermal-mechanical processes that occur during the LFW process lead to significant modification of the orientation distribution, but cause only moderate changes in the texture index.

The Sr analogue of the mineral fresnoite (Sr2TiSi2O8) is of interest as a potential storage medium for radioactive Sr from nuclear waste. No high or low temperature crystal structure information is known on this phase. Therefore high-resolution synchrotron X-ray powder diffraction measurements have been done on a synthetic sample of Sr-fresnoite in the temperature range 87-1223K. This was done as a test experiment using the HRPD beamline P02.1 at PETRA-III, DESY. Synchrotron X-ray wavelengths of 0.2067(3)Å (293K and 573-1223K) and 0.2079(3)Å (87-499K) were used. Powder diffraction data were collected with a counting time of 30s using a PerkinElmer XRD 1621 flat panel image plate detector. CeO2 was included as an internal standard to calibrate the sample to detector distance. The P4bm tetragonal crystal structure of fresnoite (Ba2TiSi2O8) was used as a starting model for Sr-fresnoite. Small amounts of SrTiO3 and SrSiO3 were also found as impurities in this sample; therefore four-phase Rietveld refinements were done. The P4bm fresnoite structure is retained over the temperature range 87-1223K.

PyFAI is an open-source Python library for Fast Azimuthal Integration which provides 1D- and 2D-azimuthal regrouping with a clean programming interface and tools for calibration. The library is suitable for interactive use in Python. In optimising the speed of the algorithms there has been no compromise on the accuracy compared to reference software. Fast integrations are obtained by the combination of an algorithm ensuring that each pixel from the detector provides a direct contribution to the final diffraction pattern and an OpenCL implementation that can use graphics cards for acceleration. This contribution describes how the algorithms were modified to work better in parallel.

Recent results of focusing and reflectivity properties of the dispersive double-bent-crystal monochromator have shown that it could be succesfully used in high resolution neutron diffraction experiment. By using a standard polycrystalline sample of α-Fe, the resolution of the diffraction performance in the vicinity of the scattering angle 2θ S = 90o for the neutron wavelength λ= 0.162 nm was tested in detail. It has been found that for thin (1.3 mm) bent second crystal the angular resolution represented by FWHM of diffraction profiles was 1x10−3 rad for 211 and 200 reflections and about 3x10−3 rad for 220 reflection.

The current report describes the installation and the preliminary commissioning of the Material Science Powder Diffraction (MSPD) beamline at the Spanish synchrotron ALBA-CELLS. The beamline is fully dedicated to powder diffraction techniques and consists of two experimental stations positioned in series: a High Pressure/Microdiffraction station and a High Resolution/High Throughput powder diffraction station.

Nuclear fuel plates based on a γU-Mo/Al mixture are proposed for research reactors. In this work their thermal behavior in the [425; 550°C] temperature range has been studied mainly by neutron and high energy X-ray diffraction. Even if complementary studies will be necessary, the kinetics of first the growth of the interaction layer between γU-Mo and Al and second of the γU-Mo destabilization have been accurately measured. This basic work should be helpful for defining manufacturing conditions for fuel plates with optimized composition.

Crystallographic structures of the three NaSbR(PO4)3 (R = Cr, Fe, In) phases were determined at room temperature from X-ray powder diffraction (XRD) data using the Rietveld analysis. The three compounds belong to the Nasicon structural family. The presence of the (303) reflection in all XRD spectra of NaSbR(PO4)3 shows clearly that all compounds crystallise in rhombohedral system with R3 space group. Na atoms are practically ordered within the two positions, 3a and 3b, of M1 sites. Structure refinements show also a partially-ordered distribution of Sb5+ and R3+ ions within the Nasicon framework. A Raman and Infrared spectroscopic study was used to obtain further structural information about the nature of bonding in NaSbR(PO4)3 (R = Cr, Fe, In) phases.

Phosphostrontium carbonate hydroxyapatites having the general formula Sr10(PO4)6(OH)(2-2x)(CO3)x were prepared by solid gas reaction at different temperatures in the range 0 ≤ x ≤ 1. Infrared spectroscopy investigation reveals a carbonate groups substituting hydroxyl ions. Intensity bands increasing with the carbonate amount introduced in the lattice, while the one corresponding to hydroxyl decreases until disappearance. The Rietveld refinement of the structural model using X-ray powder diffraction patterns is used to determine the substitution rate. It was quantified by the refinement of the occupancy sites affected by the substitution. The crystallographic study shows the evolution of the atomic coordinate in the apatite due to the carbonate incorporation. The variation of the main interatomic distances and the bond angles was also discussed.

Evidence is provided that the tridymite component observed in the X-ray diffraction patterns of some sewage sludge ashes (SSAs) should not be interpreted as the tridymite modification of SiO2 but as the tridymite form of AlPO4. This proof is based on a combined X-ray Powder Diffraction (XRD), X-ray fluorescence (XRF) and Mossbauer spectroscopy investigation of two SSAs produced at two fluidized bed incineration facilities, located in different municipalities and operated differently. The structural and chemical characterization was carried out on the ‘as received’ SSA samples as well as on the residues of these two SSAs pretreated by leaching in citric acid. In addition, direct proof is presented that the tridymite form of AlPO4 does crystallize from X-ray amorphous precursors under conditions that mimic the huge heating rate and short retention time (just seconds at T ≈ 850 °C) typical for fluidized bed incinerators.

X-ray diffraction is commonly used for non-destructive and precise quantitative determination of internal strain distributions. In recent years tomographic imaging has also been established as a powerful tool for precise non-destructive evaluation of internal structure in materials offering submicron resolution 3D imaging of density distributions. “Diffraction Strain tomography” (DST) concept (Korsunsky, Vorster et al. 2006) has been introduced as a means of tomographic reconstruction of two-dimensional internal strain distributions. The application of this approach during in situ loading has been subsequently demonstrated (Korsunsky et al., 2011). In the present study, similar acquisition strategy was used for diffraction data collection from a Ni-base superalloy turbine blade fabricated by DMLS (Direct Metal Laser Sintering, also sometimes referred to as DLD, Direct Laser Deposition). The experiment was conducted on beamline I12 (JEEP) at Diamond Light Source, UK. Each location within the object was multiply “sampled” (i.e. diffraction patterns were collected containing its contribution) by incident X-ray beams travelling through the sample at different angles. The setup of the beamline also allowed to acquire simultaneously a conventional (absorption tomography) reconstruction of the sample shape. The aim of the experiment was to obtain detailed information about the sample shape, structure, and state. The interpretation of diffraction tomography data requires precise calibration of the sample detector distance at different rotations and positions across the sample, and subsequent application of corrections to remove geometry-induced strain aberrations.

Atenolol is the most used drug in Brazil to hypertension treatment. Two crystal structures are known for this molecule: a racemic form (R,S)-atenolol and a pure form S-atenolol. The racemic form is found in commercial tablets. X-ray powder diffraction (XRD) is an adequate tool to study crystalline structures including drugs. Using the Rietveld Method with XRD data it is possible to quantify the crystalline structures existing in the raw material. Other methods like Le Bail and Pawley can be used to the profile fit and phases identification. For this work we analyzed three tablets of atenolol, two generics and the reference (materials were purchased from a drugstore at the city of Araraquara). These tablets were analyzed by Rietveld, Le Bail and Pawley methods. All tablets exhibited the racemic mixture API (R,S)-atenolol. Some crystalline excipients could be characterized: magnesium carbonate hydrate, lactose monohydrate and talc. The conclusion is that the three methods can be efficiently used to characterize the three atenolol tablets.

Powder diffraction from protein powders using in-house diffractometers is an effective tool for identification and monitoring of protein crystal forms and artifacts. As an alternative to conventional powder diffractometers a single crystal diffractometer equipped with an X-ray micro-source can be used to collect powder patterns from 1 µl samples. Using a small-angle X-ray scattering (SAXS) camera it is possible to collect data within minutes. A streamlined program has been developed for the calculation of powder patterns from pdb-coordinates, and includes correction for bulk-solvent. A number of such calculated powder patterns from insulin and lysozyme have been included in the powder diffraction database and successfully used for search-match identification. However, the fit could be much improved if peak asymmetry and multiple bulk-solvent corrections were included. When including a large number of protein data sets in the database some problems can be foreseen due to the large number of overlapping peaks in the low-angle region, and small differences in unit cell parameters between pdb-data and powder data. It is suggested that protein entries are supplied with more searchable keywords as protein name, protein type, molecular weight, source organism etc. in order to limit possible hits.

The crystal structure of the third polymorph of dibenzylsquaramide (Portell, A. et al., 2009), (fig. 1) has been determined from laboratory X-ray powder diffraction data by means of direct space methods using the computing program FOX. (Favre-Nicolin and Černý, 2002) The structure resolution has not been straightforward due to several difficulties on the indexing process and in the space group assignment. The asymmetric unit contains two different conformers, which has implied an additional difficulty during the Rietveld (Rietveld, 1969) refinement. All these issues together with particular structural features of disquaramides are discussed.