X-ray study of palladium catalysts. Influence of thermal treatment in hydrogen on the phase composition

1985 ◽  
Vol 28 (2) ◽  
pp. 373-377 ◽  
Author(s):  
D. V. Sokolskii ◽  
L. M. Kurashvili ◽  
K. Sergazieva ◽  
K. K. Kuzembaev
Keyword(s):  
Phase Composition ◽  
Thermal Treatment ◽  
Palladium Catalysts ◽  
X Ray

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

Formation of nanoscale sodium dodecahydro-closo- dodecaborate Na2[B12H12] on silicate matrix surface

2019 ◽  
Vol 484 (1) ◽  
pp. 41-43
Author(s):  
E. A. Malinina ◽  
V. K. Skachkova ◽  
I. V. Kozerozhets ◽  
V. V. Avdeeva ◽  
L. V. Goeva ◽  
...  
Keyword(s):  
Phase Composition ◽  
Ammonium Salt ◽  
Liquid Glass ◽  
Silicate Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Salt Sample ◽  
Matrix Surface

The method of nanoscaled sodium dodecahydro-closo-dodecaborate Na2[B12H12] synthesis is presented. The composite is heated to 200°C to yield the desired product, forming with the introduction of triethyl- ammonium salt [Et3NH]2[B12H12] into the silicate matrix of a sodium liquid glass. The morphology and phase composition of the synthesized sample are studied through SEM and X-ray diffraction methods, in comparison to those of a standard salt sample Na2[B12H12]. Based on the obtained data, the sample under study is an amorphous composite, on the surface of which nanoscale crystals of Na2[B12H12] form.

Phase composition depth profiles using spatially resolved energy dispersive X-ray diffraction

2004 ◽  
Vol 37 (6) ◽  
pp. 967-976 ◽  
Author(s):  
Andrew C. Jupe ◽  
Stuart R. Stock ◽  
Peter L. Lee ◽  
Nikhila N. Naik ◽  
Kimberly E. Kurtis ◽  
...  
Keyword(s):  
Phase Composition ◽  
Spatial Resolution ◽  
Zinc Coating ◽  
High Energy ◽  
Sulfate Attack ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spatially Resolved ◽  
Composition Profiles

Spatially resolved energy dispersive X-ray diffraction, using high-energy synchrotron radiation (∼35–80 keV), was used nondestructively to obtain phase composition profiles along the radii of cylindrical cement paste samples to characterize the progress of the chemical changes associated with sulfate attack on the cement. Phase distributions were acquired to depths of ∼4 mm below the specimen surface with sufficient spatial resolution to discern features less than 200 µm thick. The experimental and data analysis methods employed to obtain quantitative composition profiles are described. The spatial resolution that could be achieved is illustrated using data obtained from copper cylinders with a thin zinc coating. The measurements demonstrate that this approach is useful for nondestructively visualizing the sometimes complex transformations that take place during sulfate attack on cement-based materials. These transformations can be spatially related to microstructure as seen by computed microtomography.

Synthesis of CaWO4:(Eu3+,Tb3+) Thin Films by a Two-Step Method at Room Temperature

2013 ◽  
Vol 710 ◽  
pp. 170-173
Author(s):  
Lian Ping Chen ◽  
Yuan Hong Gao
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Composition ◽  
Room Temperature ◽  
Electrochemical Techniques ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Rare Earth Doped

It is hardly possible to obtain rare earth doped CaWO4thin films directly through electrochemical techniques. A two-step method has been proposed to synthesize CaWO4:(Eu3+,Tb3+) thin films at room temperature. X-ray diffraction, energy dispersive X-ray analysis, spectrophotometer were used to characterize their phase, composition and luminescent properties. Results reveal that (Eu3+,Tb3+)-doped CaWO4films have a tetragonal phase. When the ratio of n (Eu)/n (Tb) in the solution is up to 3:1, CaWO4:(Eu3+,Tb3+) thin film will be enriched with Tb element; on the contrary, when the ratio in the solution is lower than 1:4, CaWO4:(Eu3+,Tb3+) thin film will be enriched with Eu element. Under the excitation of 242 nm, sharp emission peaks at 612, 543, 489 and 589 nm have been observed for CaWO4:(Eu3+,Tb3+) thin films.

Study of the Bioactive Behavior of Thermally Treated Modified 58S Bioactive Glass

2008 ◽  
Vol 396-398 ◽  
pp. 131-134 ◽  
Author(s):  
Ourania Menti Goudouri ◽  
Xanthippi Chatzistavrou ◽  
Eleana Kontonasaki ◽  
Nikolaos Kantiranis ◽  
Lambrini Papadopoulou ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Bioactive Glass ◽  
Sol Gel ◽  
Bioactive Glasses ◽  
X Ray ◽  
Characteristic Temperatures ◽  
Calcium Silicates ◽  
Crystal Phases ◽  
Thermally Treated

Thermal treatment of bioactive glasses can affect their microstructure and thus their bioactivity. The aim of this study was the characterization of the thermally treated sol-gel-derived bioactive glass 58S at characteristic temperatures and the dependence of its bioactive behavior on the specific thermal treatment. The thermal behavior of the bioactive glass was studied by thermal analysis (TG/DTA). Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffractometry (XRD) were used for the characterization of the bioactive glass. The bioactive behavior in Simulated Body Fluid (SBF) was examined by Scanning Electron Microscopy (SEM-EDS) and FTIR. The major crystal phases after thermal treatment were Calcium Silicates, Wollastonite and Pseudowollastonite, while all thermally treated samples developed apatite after 48 hours in SBF. A slight enhancement of bioactivity was observed for the samples heated at the temperature range 910-970oC.

Heat treatememt effect on microstructure and mechanical properties of precipitation hardening elinvar alloy

2021 ◽  
pp. 68-73
Author(s):  
G.V. Shlyakhova ◽  
◽  
A.V. Bochkareva ◽  
M.V. Nadezhkin ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Phase Composition ◽  
Structural Analysis ◽  
Thermal Treatment ◽  
Precipitation Hardening ◽  
Physical And Mechanical Properties ◽  
Alloy Structure ◽  
Treatment Mode ◽  
Elinvar Alloy

This study presents experimental results of structural analysis, such as phase composition, grains size assessment, strength and hardness of Ni-SPAN-C alloy 902 after various heat treatment modes (hardening and aging for stress relaxation). A thermal treatment mode has been selected to obtain higher physical and mechanical properties of the elinvar alloy. It is shown that the improvement of the alloy structure in thermal treatment occurs due to the thermic stresses, as well as the formation and dissolution of intermetallides.

Thermal stability and miscibility of co-evaporated methyl ammonium lead halide (MAPbX3, X = I, Br, Cl) thin films analysed by in situ X-ray diffraction

2018 ◽  
Vol 6 (24) ◽  
pp. 11496-11506 ◽  
Author(s):  
Paul Pistor ◽  
Thomas Burwig ◽  
Carlo Brzuska ◽  
Björn Weber ◽  
Wolfgang Fränzel
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
Thermal Treatment ◽  
Phase Evolution ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray ◽  
Subsequent Thermal Treatment ◽  
Lead Halide

We present the identification of crystalline phases by in situ X-ray diffraction during growth and monitor the phase evolution during subsequent thermal treatment of CH3NH3PbX3 (X = I, Br, Cl) perovskite thin films.

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