The solid-state phase transitions of the KNO3–NH4NO3 solid solutions have been determined by high temperature X-ray diffractometry, and lattice parameter calculation has also been performed. Ammonium nitrate (AN) is of great use for gas generators of automobile air bag systems. The X-ray diffraction results showed the single (AN) phase III from 5% to 20% KNO3 in NH4NO3 and up to 373 K, which is the important temperature range for the air bag gas generator applications. The X-ray diffraction patterns of the low temperature KNO3 phase (KN II) are from 92% to 100% KNO3 composition range and up to 393 K temperature. The high temperature KNO3 phase (KN I) showed very broad composition range from 20% up to 100% KNO3 at various temperature ranges. The lattice parameters of the NH4NO3-rich (AN III) and KNO3-rich (KN II and KN I) solid solutions have been calculated at different temperature range. The volumes of AN III phase decrease from 0.3201(4) to 0.3166(1) nm3 at room temperature and from 0.3250(6) to 0.3215(3) nm3 at 373 K as the compositions increase from 5% to 20% KNO3. The lattice constants of the hexagonal KN I phase show that there is no significant change in a direction when the temperature increases. Details of X-ray results, lattice expansions, and equations during heating are presented.

The title compound, ∣Na6Li1.6K0.4Cl2∣[Al6Si6O24]‐SOD, is similar to sodalite proper, but the introduction of Li and K into the structure creates a reduction in unit-cell volume and additional collapse of the framework tetrahedra. Refinement of an X-ray powder diffraction pattern of a multiphase material yielded for sodalite a lattice parameter of 0.88427 (2) nm, an Al–O–Si bond angle of 137.9(3°), and Al–O and Si–O bond lengths of 0.1730(5) nm and 0.1620(5) nm, respectively. The angle of the unique Al–O–Si bond corresponds well with the 138° obtained by 29Si solid-state magic-angle-spinning nuclear magnetic resonance spectroscopy. This characterization is important since the compound constitutes an essential part of a radioactive waste form intended for a high-level waste repository.

The purpose of this paper is to give a rapid overview of the recent developments in the field of X-ray diffraction on polycrystalline materials from the viewpoint of the instruments. After a brief historical report, the main types of laboratory diffractometers are presented. At the end of the twentieth century the apparition of position sensitive detectors and artificial crystal monochromators have induced the conception of new diffractometer often based on old geometrical arrangements. Those modern diffractometers are described with respect to the more conventional ones. Among the experimental parameters which can characterize a given diffractometer, the instrumental resolution function and the acquisition time of the pattern are of primary importance. The different apparatus are compared with respect to those two parameters.

Ferrous nitroprusside can be obtained in three structural modifications: two different unstable phases, monoclinic trihydrate and cubic pentahydrate, and the stable one, an orthorhombic dihydrate. This contribution reports the crystal structure of the last one. Cell parameters are: a=13.9734 (2), b=7.4274 (1), and c=10.4697 (1) Å; with four formula units per cell (Z=4). The crystal structure was refined from the corresponding XRD powder pattern using the Rietveld method. Final agreement factors of the refinement process were Rwp=8.46, Rp=6.54, and S=1.38. The crystal structure is formed by a tridimensional assembling of the [Fe(CN)5NO] molecular block through iron atoms bounded at the N end of the CN ligands. The NO group remains unlinked at its O atom. The octahedral coordination of the assembling metal is completed with a coordinated water molecule which stabilizes a second water through a strong hydrogen bond interaction. The tridimensional structure appears as piled up rippled sheets leading to a system of interconnected small cavities which increase their available volume on the material dehydration. This complex loses its crystal water below 100 °C and then remains stable up to above 160 °C when the decomposition process begins with the loss of the NO ligand.

A new compound Th0.9Ce0.1SiO4, iso-typic to zircon, was prepared by heating predried ThO2, CeO2, and SiO2 (in the mole ratio 0.9:0.10:1.0) by a two-step heating protocol. The polycrystalline sample obtained was characterized by Rietveld refinement of the observed neutron diffraction data with the starting model of tetragonal ThSiO4. It has a body centered tetragonal structure with space group I41∕amd and four formula units per unit cell. The unit-cell parameters are a=7.1238(4) Å and c=6.3186(95) Å. The RP, Rwp, and Re factors are 7.77%, 10.9%, and 4.85%, respectively. The incorporation of about 10 mol % cerium was used to stabilize the tetragonal modification of ThSiO4.

The nanostructural features of the gas-phase displacement reaction 2Mg(g)+SiO2→2MgO(s)+{Si}, where SiO2 is in the form of diatom shells were studied via X-ray diffraction and Fourier methods. Diatomaceous powder heated to 700 °C in a sealed graphite cell in the presence of Mg vapor formed MgO via a displacement reaction. Warren-Averbach analysis performed on samples reacted for different times showed an initial sharp MgO grain size distribution which broadened with time. New MgO crystallization was shown to occur until about 60 min, whereafter only MgO grain growth occurred. Median MgO crystallite size increased from 7.5 to 24.9 nm during this period, whereas microstrain decreased dramatically past 60 min annealing time.

Crystal structures of A0.50SbFe(PO4)3(A=Mn, Cd) phases, obtained by solid state reaction at 920 °C, were determined at room temperature from X-ray powder diffraction (XRD) using the Rietveld method. The structures of the two samples are of the Nasicon-type with the R3 space group. Hexagonal cell parameters for A=Mn and Cd are: a=8.375(1) Å, c=21.597(2) Å and a=8.313(1) Å, c=21.996(2) Å, respectively. From XRD data, it is difficult to unambiguously distinguish between Cd2+ and Sb5+ ions in Cd0.50SbFe(PO4)3 and between Mn2+ and Fe3+ cations in Mn0.50SbFe(PO4)3. Nevertheless the overall set of cation–anion distances within the Nasicon framework clearly shows that the cation distribution can be illustrated by the {[A0.50]3a[◻0.50]3b}M1SbFe(PO4)3 (A=Mn, Cd) crystallographic formula. The divalent A2+ cations and vacancies are ordered within the two positions, 3a and 3b, of the M1 sites. Structure refinements show also a quasi-ordered distribution of Sb5+ and Fe3+ ions within the Nasicon framework. Thus, each A(3a)O6(A=Mn, Cd) octahedron shares two faces with two Fe3+O6 octahedra and each vacancy (◻(3b)O6) site is located between two Sb5+O6 octahedra.

Mechanical sensitivity of energetic materials is discussed as a function of particle size and lattice defects. Therefore an approach is made to quantify and characterize lattice defects of the energetic powders RDX and HMX using X-ray diffraction. The mechanical properties of these cyclic nitramines are supposed to be dominated by different defect mechanisms—deformation twinning and dislocation slip. The energetic powders and the line-shape standard SRM 660a (NIST) were measured on a Bragg-Brentano diffractometer D5000 (Bruker-AXS), and the diffraction patterns were evaluated by Rietveld- and peak-profile analysis using Williamson-Hall plots. Additionally, preparing samples as thin powder layers was tested in order to reduce line broadening due to low absorption. The investigations reveal interesting details. Characteristic line broadening was found for RDX and HMX pointing to a comparably higher microstrain in HMX. Anisotropic line broadening was found for RDX and discussed in terms of strain fields of dislocations.

In the course of our research on normal alkanols, the crystal structure of 1-pentanol has been solved by applying Patterson-search methods to laboratory powder X-ray diffraction data recorded on a curved position-sensitive detector (CPS120) at 183 K. The crystal structure was refined with the rigid-body Rietveld least-squares method. The cell is monoclinic, space group P21∕c, Z=4, and the cell parameters are a=15.592(9) Å, b=4.349(1) Å, c=9.157(1) Å, β=104.7(7)°, V=600.6(3) Å3. There is one molecule in the asymmetric unit with the O–H bond in gauche conformation with respect to the alkyl skeleton. Packing is defined by the hydrogen bonds linking the 1-pentanol molecules along zigzag chains parallel to b.

Materials in the Ti–Al–C ternary system commonly contain three coexisting phases, Ti3AlC2, Ti2AlC, and TiC. Quantitative phase analysis in this ternary system was investigated using X-ray diffraction. First, nonoverlap diffraction peaks were selected: the (002) peak at 2θ=9.5° for Ti3AlC2 (I∕I0=26.5), the (002) peak at 2θ=13.0° for Ti2AlC (I∕I0=39), and the (111) peak at 2θ=35.9° for TiC (I∕I0=78), respectively. Then, based on the mixing-sample method without internal standards, a set of equations was derived for determining the amounts of Ti3AlC2, Ti2AlC, and TiC in a sample using the intensities of the selected diffraction peaks. Finally, the applicability and error sources for this method were investigated. The method is simple and straightforward, and is applicable to the entire Ti–Al–C ternary system, since the derivation of this equation group is self-checking.

The microstructure evolution in pure copper deformed by rolling at liquid nitrogen temperature was determined by using X-ray diffraction peak profile analysis. The crystallite size distribution and defects evolution were determined as a function of different reduction levels (e.g., 67%, 74%, 87%, and 97%). By using the Multiple Whole-Profile fitting procedure the Fourier transforms of the experimental X-ray peak profiles were fitted all at once by theoretical calculated functions. Here it is assumed that the crystallites are spherical shape and have a log-normal size distribution. It is also supposed that the strain broadening of the profiles is caused by 〈110〉 {111}-type dislocations. The results show that the median and the variance of the crystallite size distribution decreases as the deformation reduction increases. The dislocation density has a minimum value at 74% reduction. The increase of the dislocation density at higher deformation levels is due to the nucleation of new generation of dislocations from the crystallite grain boundaries. It was found that the edge dislocation type dominate, the dislocation network formed during the deformation process.

Europium nitride (EuN), which is potentially used as an activator for nitride luminescent materials, was prepared by direct nitridation at 600 °C in a NH3 atmosphere. X-ray powder diffraction and composition analysis of the nitrided sample were carefully conducted under an oxygen-free environment. The nitrided sample was found to be mononitride with NaCl structure. An appreciable amount of oxygen (∼0.06 a.u.) was detected, but no secondary oxide phase was found. The results suggest oxygen dissolution into the lattice of EuN.

X-ray powder diffraction data are presented for nine new phases with the tetragonal tungsten bronze structure. By comparison with the structure of the M=Nb,RE=La analogue, these contain Ba in the large pentagonal sites with coordination number 15, a range of large rare-earth cations and Bi in the twelve coordinate sites, and the smaller cations, Ti and either Nb or Ta, in the octahedral framework sites. The a lattice parameter data of the tetragonal unit cell show an approximately linear variation with trivalent ion radius, apart from Dy, whose value appears to be anomalous; data for c show little variation with trivalent ion radius.

Laboratory powder X-ray microdiffraction with a focusing monocapillary and linear multichannel detector was applied to phase identification in fragments of painting layers of art works, canvas and wall paintings, and polychromes on wood. This method is useful in materials research of painting layers with complex stratigraphy, and it is indispensable in distinguishing inorganic pigments of different natural provenance and revealing degradation products. The advantage of X-ray microdiffraction is its nondestructive nature and no need of sample pretreatment. Samples after microdiffraction can hence be used for other analyses or archived. Another advantage is the possibility to work with samples smaller than 1 mm, which is particularly important in the analysis of artworks where the sample amount or size is a serious limit of using the laboratory techniques of materials research. The X-ray equipment used is more economical and more easily accessible than other microdiffraction techniques and is, hence, suitable for routine analytical work.

Methods extracting fast all the peak intensities from a complete powder diffraction pattern are reviewed. The genesis of the modern whole powder pattern decomposition methods (the so-called Pawley and Le Bail methods) is detailed and their importance and domains of application are decoded from the most cited papers citing them. It is concluded that these methods represented a decisive step toward the possibility to solve more easily, if not routinely, a structure solely from a powder sample. The review enlightens the contributions from the Louër’s group during the rising years 1987–1993.

We present a review of the application of diffraction stress∕strain analysis to small volumes. For cases in which the material properties and∕or the stress state are not homogeneous, traditional approaches may yield erroneous stress results. On the other hand, with proper care, relevant mechanical information about the system can be obtained. Through the use of conventional and synchrotron-based X-ray methods, we can determine the amount of strain transfer between thin film features that possess heterogeneous stress distributions and the underlying substrate. Two examples of such studies are presented. The resulting data are used to assess the validity of several models often used to predict the mechanical behavior in thin film∕substrate composites.

Round and spiral-shaped coil springs enable various peening angles that correspond to the surface location, and the directional shot angles may lead to a nonuniform residual stress on the coil spring surface. It is commonly known that a material under directional deformation exhibits a nonlinear 2θ-sin2ψ diagram (ψ split) due to the triaxial stress state. In this study, the residual stress distributions of spring materials deformed by shot peening at different angles were measured, and the microstructure for carbide precipitates was examined using a field-emission scanning electron microscope (FE-SEM). The nonlinearity in the 2θ-sin2ψ diagram for the shot peening samples was revealed. The extent of the ψ split increased with increasing shot peening angles, and was dependent not only on the mass fraction of carbide particles but also on the size distribution of the carbide particles.

Powder diffraction data for five three-layer Aurivillius ceramics of the form Bi2Sr2−xAxNb2TiO12 (A=Ca,Ba,x=0,0.5,1) have been determined from specimens that were characterized using both X-ray and neutron diffraction. Full Rietveld analysis demonstrated that the crystals were all tetragonal (space group I4∕mmm, #139), with highly aniostropic layered structures with lattice parameters on the order of a=3.9 Å and c=33 Å, and densities on the order of 7 g∕cm3

Ab initio crystal structure solution by powder diffraction data is based on the experimental full pattern decomposition process: the resulting structure factor moduli are used for direct phasing. The extracted intensity estimates are scarcely accurate (overlapping, background, and preferred orientation are the main causes of the lack of accuracy), no matter if Le Bail or Pawley method is adopted: consequently the structure solution process is not straightforward. We have focused our attention on the relation between the efficiency of the EXPO2004 phasing process and the various parameters which are normally used in the full pattern decomposition process, e.g., the peak shape function, the number of refinement cycles, the degree of overlapping. Different steps of the phasing process are considered: the definition of the unit cell, the determination of the space group, and the application of direct methods.

This study attempted to quantify the interstratificational broadening of the randomly interstratified illite/smectite (random I∕S) basal reflection and to evaluate the percentage of the interstratified illite layers (%I) from the result. The interstratificational broadening was quantified using the distributional discrepancy (D) defined as D=[∑t∣ft(obs)−ft(ref)∣]∕2, where ft(obs) is the frequency of a crystallite containing thickness, t (the number of layers), measured from a basal reflection broadened by interstratifications, and ft(ref) is the frequency for a basal reflection with no interstratificational broadening. The basal reflections at 5.2° 2θ under glycolation and 8.84° 2θ under thermal dehydration provided the ft(obs) and ft(ref) of random I∕S. The linear relation, D=2.17%I+2.49(0⩽%I⩽30), was obtained from simulations for SWy-2 (Wyoming, USA).