The phase identification of a polycrystalline mixture by X-ray powder diffraction data is often requested for studying materials interesting to different scientific and technological fields: chemistry, pharmaceutics, mineralogy, archeometry, forensic science, etc. The availability of user friendly computer programs, able to carry out qualitative phase analysis in efficient and possibly automatic way, is extremely useful to the scientific community involved in powder diffraction. QUALX2.0, the evolution of QUALX, is a freely distributed software for qualitative phase analysis. Based on the traditional search–match method, it is able to manage both a commercial database (PDF-2 maintained by ICDD), and a freely available database (POW_COD generated by the structure information contained in the Crystallography Open Database). QUALX2.0 is continuously improved in terms of computing and graphic tools. Correspondingly, the database POW_COD is suitably modified to make efficient the operations of search. The search–match approach can be facilitated by the use of restraints, when available, involving the chemical composition, the kind of compound(s) (e.g., organic, inorganic, etc.), the symmetry (space group, crystal system), the unit-cell parameters and/or volume, the crystal properties (measured and/or calculated crystal density, crystal color). An outline of the main features of QUALX2.0 and an example of application is described.

In this work, a poorly water-soluble drug (efavirenz) was mechanically activated by ball-milling. The effect of the mechanical activation on the dissolution behavior was investigated considering changes in the particle size and morphology. The powder diffraction was used to follow the comminution process, verifying phase compositions, and crystalline domain size. The interplay between domain and grain size was studied in relation to the solubility rate, through specific dissolution tests. Finally, the morphological characterization has allowed to complete the physical–chemical characterization of the milled powders. This study demonstrated that the mechanical activation of the drug leads the particle size reduction and, with a long milling time, morphological changes. The grain size reduction is not always sufficient to increase the solubility: morphology and agglomeration grade play an important role in the dissolution process.

This study investigates the morphology changes in thin diblock copolymer (DiBCP) films occurring in the interaction with modified nanoparticles (NPs). Magnetite (Fe3O4) and silica (SiOx) were prepared and used. Poly(pentyl methacrylate-b-methyl methacrylate) (PPMA-b-PMMA) (70/30 mol mol−1, hcp cylinders of the PMMA phase) DiBCP were employed to prepare thin films having thicknesses to realize standing cylinders in pure DiBCP films. The investigations aimed at two topics: (1) morphology after controlled incorporation of organo-modified NP (gold, silver, Fe3O4, SiOx) and (2) additional solvent vapour annealing (SVA) with tetrahydrofuran (and chloroform for comparison). The laterally ordered morphology in thin films was examined by GISAXS and atomic force microscopy. Keeping the same type of morphology in nanocomposites, the dimensions of the periodic nanostructure altered depending on type and amount of incorporated NP. It was found that SiOx clusters enlarge the lateral distance of the PMMA cylinders, whereas metallic NPs reduce this parameter. Applying SVA improves the phase separation slightly, whereas lateral distances were kept constant or were reduced a little. Switching of domain orientation upon SVA could not be detected in the presence of NPs located at the polymer/substrate interface.

A combined X-ray powder diffraction (XPD) and high-resolution extended X-ray absorption fine structure (EXAFS) at the Co and Ga K-edges study has been performed for LaCoO3 and LaGaO3 ceramics, the latter sample was used as a reference without spin transitions. Based on the X-ray diffraction data, we have found that isotropic atomic displacement parameters (ADP) or mean-squared displacement of the Co–O bond exhibit gradual growth below ~50 K, wherein the strain dependencies testify rapid increase below 150 K for the LaCoO3 having rhombohedral structure. No similar features could be observed for LaGaO3 sample. Above ~100 K the isotropic ADP of the Co–O bond indicate a gradual growth, whereas strain curves show distinct bend near the spin-state transition temperature at about 150 K. According to the EXAFS data, the correlated parallel mean squared relative displacement (MSRD||) of Co–O and Ga–O bonds exhibit a gradual growth above 150 K; however, in the LaCoO3 this parameter is notably bigger. It is supposed that at low temperature the cobalt ions are dominantly in low-spin (LS) state, while certain amount of Co3+ ions located within the surface layer of the crystallines have high-spin state (HS). Temperature growth leads to a gradual transformation of the HS state of the cobalt ions into the highly-hybridized intermediate-spin (IS) state, while the cobalt ions located in the inner part of the crystallines remain LS configuration up to 150 K. Further temperature increase leads to a spin transition of the Co3+ ions located within the crystallines from the LS state into the IS one.

X-ray diffraction (XRD) pattern of nanosized equimolar solid solution CoIr prepared by thermolysis of [Co(NH3)6][Ir(C2O4)3] contains peaks characteristic of both face-centered cubic (fcc) and hexagonal close-packed (hcp) structure. Moreover, 101 peak of hcp modification is substantially wider than 100 and 002 peaks, 102 and 103 are very broad and almost invisible. Peak 200 of fcc structure is wider than the other peaks of this modification and slightly shifted toward lower angles. It was shown by simulation of XRD patterns that particles of CoIr alloy are nanoheterogeneous and consist of lamellar domains having fcc and hcp structures. The best fit was obtained for the following model parameters: an average crystallites size is about 10 nm, average thicknesses of the fcc and hcp domains are 1.7 and 1.1 respectively. The presence of domain structure was confirmed by transmission electron microscopy data.

The evaluation of the performance of a geological barrier, consisting essentially of a clay matrix, in the context of industrial and household waste confinement must go with the study of its hydration behavior respectively under extreme atmospheric conditions and variable mechanical soil constraints. Na-montmorillonite (Swy-2) is used, as starting materials, in order to establish the link between applied externals strain (variable relative humidity rate %RH and axial mechanical constraint) and the hydration material response. All constraints are realized at the laboratory scale. This work is achieved using oedometric testing and quantitative X-ray diffraction (XRD) analysis, based on the modeling approach, which consists in the comparison of experimental 00l reflections with the calculated ones deduced from structural models. This approach allows us to quantify the interlamellar space configuration and all structural changes along the c* axis. Obtained results show a decrease for the void ratio e value along the compaction/reswelling process. The “insitu” XRD analysis realized at 5%RH demonstrates hydration shift, from dehydrated water layer (i.e. 0W) to monohydrated water layer (i.e. 1W), attributed to the applied mechanical constraint. At 90%RH, the sample hydration state remains at tri-hydrated water layer (3W) with a clear interstratified trends.

The system of phosphates Ca9−xPbxHo(PO4)7 were obtained by solid-state reaction and were found to be isotypic with whitlockite-type β-Ca3(PO4)2 (polar space group R3c). The crystal structure encloses five crystallographic sites M1–M5 different in size and oxygen coordination. The unit-cell parameters were determinate using Le Bail decomposition. Rietveld method structural refining showed that Ho3+ ions are located statistically with calcium in M1 and M2 sites, while Pb2+-ions are located in the M3 site. Examination of optical second-harmonic generation evidences non-linear optical activity and confirms polar space group R3c. Structural mechanisms and dielectric features of phase transitions are strongly influenced by the exact distributions of atoms over the crystallographic sites.

A powder diffraction measurement system constructed on a beam-line BL5S2 at Aichi Synchrotron Radiation Center in Seto, Japan, has been modified for extensive use of two-dimensional (2D) X-ray detectors. Four flat 2D detectors are currently mounted on the movable stages on supporting rods radially attached to the 2Θ-wheel of the goniometer with the interval of 25°. The 2D powder diffraction intensity data are reduced to conventional 1D format of powder diffraction data by the method based on averaging of the pixel intensities with geometrical corrections, which also enables evaluation of standard uncertainties about the reduced intensity data. The 1D powder diffraction data of a 0.1 mm-capillary LaB6 (NIST SRM660b) sample obtained at the camera length of 340 mm have shown almost symmetric peak profile with slight asymmetry simulated by a beta-distribution profile function.

Computational methods and a program to obtain crystal structures that have the perfectly identical diffraction patterns, i.e. structure factors with the same absolute values and the same lattice symmetry are discussed. This is directly related to the uniqueness of solutions in crystal structure determination of single-crystal/powder-crystal samples from diffraction data. In order to solve the problem, it is necessary to solve a system of quadratic equations. The framework of positive-semidefinite programming is used herein to solve the system efficiently.

The study presents the results of the influence of high-energy ball-milling time on the structure of the new β-type Ti–Ta–Nb–Zr alloys for biomedical applications. Initial elemental powders were mechanically alloyed in a planetary high-energy ball mill at different milling times (from 10 to 90 h). Observation of the powder morphology after various stages of milling leads to the conclusion that with the increase of the milling time the size of the powder particles as well as the degree of aggregation change. Clear tendency of crystalline size reduction at every stage of the grinding process is clearly observed. The X-ray diffraction results confirmed the formation of β phase during high-energy ball milling of the precursor mixture of Ti, Ta, Nb, and Zr. The Rietveld refinement method has shown that both the production method and the atomic radii of the elements used in the mechanical synthesis have influence on the structure. Furthermore, it was found that a broadening of the diffraction peaks with increase of the milling time results from an increase in the crystallites dispersion and an enlargement in the lattice distortion. The results indicate that this technique is a powerful and high productive process for preparing new β-titanium alloys with nanocrystalline structure and appropriate morphology.

This paper reports the first successful synthesis and the structural characterization of nanocrystalline and stacking-disordered β-cristobalite AlPO4 that is chemically stabilized down to room temperature and free of crystalline impurity phases. Several batches of the title compound were synthesized and thoroughly characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray spectroscopy mapping in SEM, solid-state 31P nuclear magnetic resonance (31P-NMR) spectroscopy including the TRAPDOR method, differential thermal analysis (DTA), gas-sorption methods, optical emission spectroscopy, X-ray fluorescence spectroscopy, and ion chromatography. Parameters that are critical for the synthesis were identified and optimized. The synthesis procedure yields reproducible results and is well documented. A high-quality XRD pattern of the title compound is presented, which was collected with monochromatic copper radiation at room temperature in a wide 2θ range of 5°–100°.

The thermomechanical processing of NiTi shape memory alloys usually involves several steps of hot and/or cold deformation. The present work presents the structural characterization of a Ni-rich NiTi alloy bar, produced by vacuum-induced melting and thermomechanical processing in laboratory scale, aiming at massive production in the future. This study focused on the first step of hot working at 800 °C during rotary forging. Microstructural characterization was performed using differential scanning calorimetry, high- and low-temperature X-ray diffraction (XRD) using a laboratory source and synchrotron XRD. Thus, it was possible to obtain the phase transformation characteristics of the material: the transformation temperatures and the transformation sequence. Proposed thermomechanical processing is intended for production of bars and wires that will be subsequently drawn to get thin wires, for different applications, including orthodontic arch wires.

The thermal behavior and decomposition reaction of Prussian blue (PB) (Fe43+[Fe2+(CN)6]3·xH2O) was studied under inert atmosphere of argon by simultaneous thermogravimetry and differential scanning calorimetry, from room temperature up to 900 °C, with a heating rate of 5 K min−1. Parallel to the thermogravimetric measurements, the thermal process was monitored by in situ X-ray powder diffraction (XRD) technique under nitrogen atmosphere. The thermogravimetric data show six steps, corresponding to different stages of the decomposition reaction; comparable results are also obtained by in situ XRD. In addition, a set of PB samples heated up to selected temperatures (190, 300, 370, 540, 680, and 790 °C) were ex situ analyzed by powder XRD and Mössbauer spectroscopy. It is found that PB exhibits a negative thermal expansion prior to the water release from its crystalline lattice. Above 300 °C, the decomposition is based on the release of cyanogen gas from the PB structure. At 370 °C, a cubic iron cyanide compound is formed, while at higher temperatures several iron carbides were found. The subsequent thermal treatment of these carbides leads to the formation of metallic iron and graphite.

The program FAULTS has been used to simulate the X-ray powder diffraction (XRD), neutron powder diffraction (NPD), and electron diffraction (ED) patterns of several structural models for LiNi1/3Mn1/3Co1/3O2, including different types of ordering of the transition metal (TM) cations in the TM slabs, different amounts of Li+/NiII+ cation mixing and different amounts of stacking faults. The results demonstrate the relevance of the structural information provided by NPD and ED data as compared with XRD to characterize the microstructure of NMC (LiNi1−y-zMnyCozO2) compounds.

Precipitation of secondary intermetallic phases in aluminium alloy Al7075 sintered by spark plasma sintering method from powders milled at room and cryogenic temperature was studied by X-ray powder diffraction. Deformation energy stored during cryogenic milling influences the precipitation in Al7075 alloy. High temperature X-ray diffraction experiment revealed the potential for further precipitation strengthening of samples prepared by spark plasma sintering of milled powders. It was established that the correction of absorption edge of metal Kβ-line filter used for laboratory sources greatly enhances the precision of quantitative Rietveld analysis as well as the determination of precipitates’ crystallite sizes.

X-ray diffraction (XRD) and X-ray fluorescence (XRF) are widely used analytical techniques for materials characterization; the information they provide can be considered complementary, as the former is mostly used to obtain crystallographic information and analyze phase content, whereas the latter is sensitive to elemental composition. Many researchers and technologists working in a variety of application fields already use them together in some sort of a “combined” approach, by separately performing XRD and XRF data collection and analysis on the same sample and then comparing the analytical results obtained to integrate and complement the respective analytical information. In this work, we propose a true combined approach to merge both XRD and XRF data acquisition and analysis. Custom analytical X-ray instrumentation has been developed to perform the simultaneous data acquisition, by using a single X-ray source and dedicated detectors to collect the diffracted and fluorescent X-ray photons from the same sample volume. Additionally, a combined XRD/XRF data analysis methodology has been implemented by extending Rietveld based code to incorporate the full pattern fitting of XRF spectra starting from the phases instead of a simple matrix elemental composition. We report two analytical examples from different application fields to better illustrate the capabilities of the proposed approach.