In this paper, we present a comprehensive study of the order-disorder and order-order processes in palladium-yttrium alloys, which are Pd1-xYx (x = 8.49; 9.08 at%). For this study, we used precision X-ray diffraction (XRD) using synchrotron radiation (SR), scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Deformed and homogenized annealed samples were selected for this study, denoted as "rolled" and "annealed", respectively. We have shown the complex structural effects of heat treatment and reversible hydrogen doping on the order-order and disorder-order processes in the alloys. New experimental results were obtained for the long-ordered superstructure (LPS) and Pd7Y superstructure. One finding is the increased stability of the LPS against heating and hydrogenation compared to the Pd7Y ordering. A comparative analysis of the physical broadening of superstructural reflections is presented.

This article is about palladium-based membrane alloys with promising characteristics. Lead concentration in samples is 5 and 20 wt%. The samples are prepared from high purity metals (99.95 wt%). The samples are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Effect of the concentration of alloying components on the Debye temperature and on the mean-square displacements of atoms is determined. Influence of defects of the first class (point defect - vacancy pairs, pores, dislocation loops of small radius) found to be dominant in alloys.

The effect of Pb small additives on the microstructure and phase composition of palladium-based diffusion membrane-filters was studied in this work. In the present study, we comprehensively investigated the lead-containing palladium alloy by X-ray diffraction using synchrotron radiation and high-resolution scanning electron microscopy. The predisposition of the alloy to the formation of a conditionally homogeneous nanodisperse substructure with small values of micro-deformations is established. The stable preservation of the phase composition during a single hydrogenation is revealed.

The evolution of a nanostructured state of palladium-lead membrane alloys during their interaction with hydrogen was studied using precision X-ray diffraction with synchrotron radiation (SR) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDXS). The importance of this topic is due to the need and demand for improving the performance characteristics of dense metal diffusion filters for high purity hydrogen separation processes. Palladium-based membrane filters with lead concentrations of 5 and 20 wt.% were prepared via electric arc melting from high purity metals (99.95%). The thickness of the filters was 50 μm. Hydrogenation was carried out from a gas medium at 573 K and the pressure of 16 atm. within 150 min. The focus of the study is on the structural state of diffusion filter membranes depending on the content of the palladium-alloying element-lead-and on analysis of the substructure of alloys before and 5300 h relaxation after hydrogenation is carried out. Specific features of the surface morphology and the structure of the membrane filters depending on the concentration of lead in the alloys are determined. The formation and development of deformation processes in metal systems upon the hydrogenation is shown. The establishment of peculiarities of hydrogen interaction with metals will contribute to obtaining new potentially important characteristics of membrane filters.

The features of establishing the hydride state of palladium-based membrane alloys with doping elements ruthenium, lead and yttrium are investigated by X-ray diffraction (XRD) using synchrotron radiation (SR). The solution of the development of methods for controlled diffusion interaction of hydrogen with metal systems, including the use of reversible hydrogen doping in order to influence physical and chemical properties metallic systems is the aim of the study. After hydrogenation the hydrogen content in the alloys was determined by changing the crystal lattice constant. The Vickers method is used to determine the hardness of membrane alloys surface before and after their doping with hydrogen.

Magnetic properties of the R2Fe17 compounds are sensitive to the atomic substitutions and interstitial absorption of nitrogen. In our work, both were combined and their effect on the magnetization behavior of Er2Fe17 compound in magnetic fields up to 58 T was studied. Er2Fe17N2, Sm1.2Er0.8Fe17N2 and Sm1.8Er0.2Fe17N2.1 nitrides were prepared. Magnetization measurements were carried out, mainly on powder samples (excluding Er2Fe17 single crystal). Nanopowders of Sm1.2Er0.8Fe17N2 were obtained by mechanical grinding. The grinding time was varied from 0 to 60 minutes. The strength of the inter-sublattice coupling in samples is estimated by analyzing high-field magnetization data.

Методом прецизионной рентгеновской дифрактометрии проведено исследование фольги сплава системы Pd-In-Ru после электролитического гидрирования. Обнаружено увеличение рассеивающего объема образца и его многофазный распад в результате α —> β превращения. Установлены основные характеристики этого процесса.

The methods of small angle synchrotron radiation scattering, vibration spectroscopy, and second harmonic generation are applied to glasses of the K 2 O-TiO 2 -P 2 O 5 system near the stoichiometry of potassium titanyl-phosphate to demonstrate that at the initial stage of phase separation, while glass remains x-ray amorphous and clear, it can possess quadratic optical nonlinearity. The emergence of nonlinearity is facilitated by the formation of nanoheterogeneities in glass whose structure resembles the structural pattern of a nonlinear-optical crystal. Acorrelation established between the structural specifics of x-ray amorphous glass and its quadratic optical nonlinearly suggests the advisability of describing the short-range and medium-range orders of glasses at the glass-formation boundary in the context of quasicrystallite models.

Glasses at early stages of phase separation, while remaining amorphous, are shown to possess or not to possess second-order optical nonlinearity (SON) depending on specific features of their short-range/medium range order and nanoinhomogeneous structure characterized with IR and Raman spectroscopy, X-ray diffraction, small-angle X-ray and neutron scattering and second harmonic generation (SHG). In the present work it is demonstrated by the example of potassium titanium phosphate glasses of composition near KTiOPO4 stoichiometry. Formation of nanoinhomogeneities, structure of which is similar to the structural motif of some non-linear optical (NLO) crystal, favors SON. Heat treatment of such glasses at temperatures near glass-transition temperature Tg stimulates remarkable SON enhancement keeping transparency and amorphous state. While temperature is increasing SHG grows up to values, comparable with those of NLO crystals with rise of Bragg reflections in the X-ray diffraction pattern of the glass and decrease of its transparency. Revealing correlations between structural peculiarities of glasses and their SON argues preference of description of shortand medium-range order in glasses with composition close to boundaries of glass-forming regions from the position of quasi-crystallite models. 2006 Elsevier B.V. All rights reserved.

Glasses at early stages of phase separation, while remaining amorphous, are shown to possess or not to possess second-order optical nonlinearity (SON) depending on specific features of their short-range/medium range order and nanoinhomogeneous structure characterized with IR and Raman spectroscopy, X-ray diffraction, small-angle X-ray and neutron scattering and second harmonic generation (SHG). In the present work it is demonstrated by the example of potassium titanium phosphate glasses of composition near KTiOPO4 stoichiometry. Formation of nanoinhomogeneities, structure of which is similar to the structural motif of some non-linear optical (NLO) crystal, favors SON. Heat treatment of such glasses at temperatures near glass-transition temperature Tg stimulates remarkable SON enhancement keeping transparency and amorphous state. While temperature is increasing SHG grows up to values, comparable with those of NLO crystals with rise of Bragg reflections in the X-ray diffraction pattern of the glass and decrease of its transparency. Revealing correlations between structural peculiarities of glasses and their SON argues preference of description of short- and medium-range order in glasses with composition close to boundaries of glass-forming regions from the position of quasi-crystallite models.

Glasses from which the ferroelectrics phase KTiOPO4 can crystallise have been prepared and studied. Namely, two glasses having the 92(K2O·2TiO2·P2O5)·8SiO2 (KTP-8Si) and the 88(K2O·2TiO2·P2O5)·12SiO2 (KTP-12Si) molar compositions have been synthesised by the melt quenching technique. They were examined by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The KTP-8Si glass devitrifies in a single step forming KTiOPO4 phase, whereas the KTP-12Si glass firstly crystallises in an unknown phase and then, at higher temperatures, KTiOPO4 crystallites grow. Proper heat treatments performed on the KTP-8Si glass at temperatures just below the glass transition range produce transparent samples the glassy matrix of which contains crystalline nanostructure of the KTP phase.

Transparent glasses composition of which can be expressed by the formula: (100−x)·(K2O·2TiO2·P2O5)·x(K2O·2B2O3·7SiO2), where x=5, 10, 15 and 20 mol% (KTP–xKBS), were obtained by melt quenching technique. The structure and crystallization behavior of these glasses have been examined by Fourier transform infrared spectroscopy, differential thermal analysis and X-ray diffraction. In spite of their nominal composition, the studied glasses exhibit a similar oxygen polyhedra distribution. However, significant differences were found in the trigonal BO3 units amount. During DTA runs all the examined glasses devitrify in two steps. In the former, very small crystals of an unknown crystalline phase are produced. In KTP–5KBS and KTP–10KBS glasses anatase phase was also detected. Attempts were made in order to identify the unknown phase (UTP) for which a AB3(XO4)2(OH)6 Crandallite-type structure was proposed where the A, B and X sites were occupied by K, Ti and/or Al, and P, respectively. In the second devitrification step the crystallization of the KTiOPO4 phase occurs while the UTP phase previously formed disappears. Isothermal heat treatments performed at temperature just above Tg have allowed one to obtain transparent crystal–glass nanocomposites, formed by crystalline nanostructure of the UTP phase uniformly dispersed in the amorphous matrix.