For residual stress evaluation in complex substrate-coating systems, energy-dispersive (ED) diffraction with energies up to 100 keV can be applied to analyze the near interface residual stress state in the substrate, because the high energy white beam penetrates the coating completely. By the example of an Al2O3/TiCN on WC coating system we have studied the feasibility for using the coating reflections being stored in the ED diffraction patterns together with the substrate diffraction lines to analyze the residual stress state in individual sublayers of which the coating system consists. The results indicate that the ED method is suitable to detect even steep intralayer stress gradients, if the diffraction conditions are adapted to the coating geometry.

Quaternary compound CuZnGa3Te6 was synthesized by the melt and anneal technique. The defect-tetrahedral structure compound crystallized in the tetragonal unit cell with possible space group I4 and Z=4/3. Complete powder diffraction data were obtained and unit cell parameters a and c, and X-ray density were calculated. These were a=0.5946(2) nm, c=1.1891(5) nm, and Dx=5.81×103 kg/m3.

Two applications of parametric Rietveld refinement employing a newly developed robust computer program are presented. The first application focuses on the parametric kinetic analysis of the reactions involving phase transitions of various polymorphic forms of copper phthalocyanine pigments. The second application concerns the parameterization of crystallite size with respect to experimental temperature. XRPD data for nanocrystalline titanium dioxide measured in dependence on temperature are used in this case study. Both the applications were realized with the help of the developed program in combination with the launch mode of topas® software.

Total reflection X-ray fluorescence analysis (TXRF) using monochromatized undulator radiation in the PTB radiometry laboratory at the synchrotron radiation facility BESSY II has been employed to investigate the chemical state of nitrogen compounds in aerosols. The aerosol samples of different size fractions were deposited on silicon wafer surfaces in a May impactor. Using a thin window Si(Li) detector, TXRF detection limits for nitrogen are in the upper fg and lower pg range. Taking advantage of the tunability of monochromatized undulator radiation, the near edge X-ray absorption fine structure (NEXAFS) could be combined with TXRF analysis, allowing for the speciation of the aerosols at the nitrogen K absorption edge. Such low detection limits enable an analysis of aerosol samples taken in 10 min with acceptable accuracy. Applicability of the technique to real aerosol samples has been used to compare nitrogen oxidation state in suburban and rural aerosols

The crystal structure of several compounds of Ca1−xSrxZr4(PO4)6 ceramics has been investigated by X-ray powder diffraction at room temperature. All compounds form a solid solution with a unique unit cell. While the lattice parameter a of the hexagonal unit cell decreases of about 0.9% with increasing Sr content only slightly, it considerably elongates in c direction (2.8%). No structural transformation has been observed by high-temperature X-ray diffraction up to 1000 °C.

X-ray powder diffraction was used to study the phase composition of human renal calculi. The stones were collected from 56 donors in Vitória, Espírito Santo state, southeastern Brazil. An XRD phase quantification revealed that 61% of the studied renal stones were composed exclusively of calcium oxalate [34% formed only by calcium oxalate monohydrate (COM) and 27% presents both monohydrate and dihydratate calcium oxalate]. The 39% multi-composed calculi have various other phases such as uric acid and calcium phosphate. Rietveld refinement of XRD data of one apparent monophasic (COM) renal calculus revealed the presence of a small amount of hydroxyapatite. The presence of this second phase and the morphology of the stone (ellipsoidal) indicated that this calculus can be classified as non-papillary type and its nucleation process developed in closed kidney cavities. In order to show some advantages of the X-ray powder diffraction technique, a study of the phase transformation of monohydrate calcium oxalate into calcium carbonate (CaCO3) was carried out by annealing of a monophasic COM calculi at 200, 300, and 400 °C for 48 h in a N2 gas atmosphere. The results of the XRD for the heat treated samples is in good agreement with the thermogravimetric analysis found in the literature and shows that X-ray powder diffraction can be used as a suitable technique to study the composition and phase diagram of renal calculi.

Samples of single-phase Sr2FeMoO6 were successfully prepared by solid-state reaction with long sintering times. The crystal structures of the Sr2FeMoO6 samples were determined from X-ray powder diffraction data using the Rietveld refinement method. The structure results obtained by the Rietveld refinements show that an increase in the total sintering time of the solid-state reaction is an effective method to obtain single Sr2FeMoO6 phase and to improve the ordering of Fe and Mo cations (or reducing antisite defects) in the double-perovskite structure. The volume of the tetragonal unit cell of Sr2FeMoO6 contracts slightly after successive sintering treatments. The averaged Fe-O and Mo-O bond lengths as well as the tilt between the FeO6 and the MoO6 octahedra decrease with increasing total sintering time. Our results suggest that the detected subtle changes in crystal structure, such as bond lengths and bond angles between the Fe and Mo cations and oxygen, in the ordered double-perovskite structure may be responsible for the large effects on previously reported transport and magnetic properties of an oxide metal.

The compound Er2BaF8 is prepared by heating appropriate amounts of BaF2 and ErF3 at 900 °C for 18 h in a dry argon filled quartz ampoule. The polycrystalline sample obtained was characterized by a Rietveld refinement of the observed powder diffraction data. This compound crystallizes in a monoclinic lattice with unit cell parameters: a=6.9620(2), b=10.4960(3), c=4.2541(1) Å and β=99.685(1)°, V=306.14(1) Å3, Z=2, (space group C 2/m, No. 12). The structure analysis reveals the presence of one kind of Ba and Er atoms in the unit cell. There are three different kinds of fluorine atoms, namely F1, F2, and F3 in the ratio of 8:4:4. The Er atoms form a square-antiprism polyhedron with eight fluorine atoms, which share three of its edges to form a ring of six ErF8 polyhedra. The rings of ErF8 polyhedra are connected via two opposite corners along the c-axis of the unit cell. The voids formed within the rings are occupied by Ba atoms, which maintain a twelve-coordination polyhedron with the fluorine atoms. As per the Rietveld analysis, the F3 site may exist as a disordered state by shifting the fluorine atom from the two-fold axes. © 2004 International Centre for Diffraction Data.

Stress in the early stages of growth has been measured in α-Al2O3 (alumina) scales formed on FeCrAl- and NiAl-based alloys during heating in air at 1000 °C to 1200 °C. Scale thickness ranges from 0.5 to 5 μm, times from 5 to 720 min. Stress was measured using the multiple-tilt method. In order to measure the thinnest scales at the earliest times, focused, monochromatic synchrotron radiation was used for high intensity, and a fixed, small angle of incidence was used along with an appropriate wavelength to maximize scattering from the film relative to the background from the substrate. Depending on the composition, transient tensile stresses of up to 1.2 GPa were observed, with maximum stress at times ranging from >10 h at 1000 °C to <10 min at 1200 °C. Thermal stresses induced by an abrupt temperature change were found to relax much more quickly, suggesting that the kinetics observed during isothermal growth reflect a dynamic competition between stress generation and stress relaxation. These results challenge commonly accepted models of growth stress in scales that predict that a compressive stress will be generated as the metal converts to a larger-volume oxide in a constrained location such as an interface. The observed tensile stress may be due to another mechanism altogether (e.g., grain coalescence), or to the conversion of a transitional Al2O3 to the equilibrium α-Al2O3 phase. For one composition, transitional Al2O3 is observed during the period of tensile stress

The crystal structures of the chiolite-related room temperature phases α-Na5M3F14 (MIII=Cr,Fe,Ga) are determined. For all of them, the space group is P21/n, Z=2; a=10.5096(3) Å, b=7.2253(2) Å, c=7.2713(2) Å, β=90.6753(7)° (M=Cr); a=10.4342(7) Å, b=7.3418(6) Å, c=7.4023(6) Å, β=90.799(5)° (M=Fe), and a=10.4052(1) Å, b=7.2251(1) Å, c=7.2689(1), β=90.6640(4)° (M=Ga). Rietveld refinements produce final RF factors 0.036, 0.033, and 0.035, and RWP factors, 0.125, 0.116, and 0.096, for MIII=Cr, Fe, and Ga, respectively. The MF6 polyhedra in the defective isolated perovskite-like layers deviate very few from perfect octahedra. Subtle octahedra tiltings lead to the symmetry decrease from the P4/mnc space group adopted by the Na5Al3F14 chiolite aristotype to the P21/n space group adopted by the title series. Facile twinning precluded till now the precise characterization of these compounds.

Polycrystalline Mn1.1Fe0.9P0.76Ge0.24 was prepared by mechanical alloying and spark plasma sintering. Neutron diffraction was used to determine the structure of the title compound, and its nuclear and magnetic structures were refined using the Rietveld method. It is found that temperature and magnetic field can induce phase transition between the paramagnetic and the ferromagnetic phases in the material, and the paramagnetic and ferromagnetic phases have very distinct crystal structures and different Ge contents.

Release 2003 of the Powder Diffraction File (PDF) contains ∼280 000 unique entries organized in a series of tables in a relational database format. The PDF is available in two products, PDF-4/Full File and PDF-4/Organics, which allow users to access and query over 150 million filled entry fields. An editorial database is used to generate the commercial products that contain tables of experimental details and statistical evaluation criteria used by the editors to evaluate quality and determine quality marks for each entry in the PDF. This editorial database has nearly doubled the searchable entry fields. This database was mined to evaluate experimental methods in X-ray diffraction. Both experimental powder diffraction data and data calculated from predominantly single crystal X-ray structural analyses were assigned statistical quality criteria. For experimental powder data, the average delta two theta values for all d-spacings in the entry set were used. Calculated data were evaluated using R factor values as the primary quality criteria. A Quality Index, which measures the errors in refined unit cell parameters divided by the magnitude of the cell parameter, can be used to compare all types of data. Experimental variables were then analyzed versus these criteria. Variables include optic configuration, (i.e., Seeman–Bohlin, Guinier, Debye–Scherrer), use of internal and external standards, use of monochromators, wavelength divergence, wavelength selection, equipment radius, specimen transparency, and specimen absorption. This study significantly differs from prior round robin analyses in that the use of the database allows us to study very large population sets for every variable analyzed.

Four matrix-phase crystallographic directions of IN718 are investigated by in situ tensile tests using neutron diffraction. The elastic diffraction constants for all directions measured are compared to theoretical values calculated by the Kröner model. The differences between the microscopic and the macroscopic material response are given. The accumulation of microstrains in the different crystallographic directions is discussed. A comparison between the results of a single phase material (ingot IN718) and two differently thermal treated multiphase materials is presented.

The structural and magnetic properties of the DyCo4−xFexGa compounds with x=0, 0.5, 1, and 1.5 have been investigated by X-ray diffraction and magnetic measurements. Powder X-ray diffraction analysis reveals that each of the DyCo4−xFexGa compounds has a hexagonal CaCu5-type structure (space group P6/mmm). The Fe solubility limit in DyCo4−xFexGa is x<1.5. The higher the value of x, the larger the unit-cell parameters a, c, V, and the 3d-sublattice moment but the smaller the 3d uniaxial anisotropy. Magnetic measurements show that the Curie temperature of DyCo4−xFexGa increases from 498 K for x=0 to 530 K for x=1.5, the compensation temperature Tcomp decreases from 286 K for x=0 to 238 K for x=1.5, and the spin-reorientation transition temperature increases from 403 K for x=0 to 530 K for x=0.5. No spin-reorientation transition was found in the samples with x=1.0 and 1.5. The saturation magnetization of DyCo4−xFexGa measured at 173 K increases but the magnetization measured at 300 K decreases with increasing Fe content x.

(Pr0.55Ca0.45)(Mn1−yCry)O3 (with y=0.00, 0.03, and 0.06) have been prepared by means of a solid state reaction from stoichiometric powder mixtures of binary oxides. X-ray powder diffraction analysis reveals the formation of the perovskite-type compound for the whole considered compositions; no evidence for secondary phases may be detected. The structural refinements have been carried out using X-ray powder diffraction data applying the Rietveld method; the lattice parameters of the orthorhombic cell faintly change with composition. On the contrary the tilting of the octahedra results are strongly dependent on the concentration of Cr in the 4b site. Bond valence sum method has been applied in order to evaluate the possible presence of lattice-induced strains and the amount of Mn4+. Structural data are also reported.