Synchrotron x-ray diffraction analysis of gadolinium and lanthanum titanate oxides irradiated by xenon and tantalum swift heavy ions

2015 ◽  
Vol 1743 ◽  
Author(s):  
Sulgiye Park ◽  
Maik Lang ◽  
Cameron L. Tracy ◽  
Fuxiang Zhang ◽  
Christina Trautmann ◽  
...  
Keyword(s):  
Cross Sections ◽  
Heavy Ions ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Swift Heavy Ions ◽  
Lanthanum Titanate ◽  
Radiation Induced ◽  
Consistent Increase ◽  
Track Diameter

ABSTRACTA synthetic cubic pyrochlore, Gd2Ti2O7 (Fd3̅m) irradiated with swift heavy ions is compared with a compositionally-related composition La2Ti2O7 (P21), which has a monoclinic, layered, perovskite-type structure. Irradiation experiments were performed at the GSI Helmholtz Center with 181Ta ions and 129Xe ions at specific energies of 11MeV/amu. At these energies the ions pass entirely through the sample thickness of ∼ 40 μm. Angle-dispersive synchrotron powder x-ray diffraction (XRD) measurements were completed and an increasing ion-induced amorphization with increasing ion fluence was for both phases. The ion track cross-sections for the radiation-induced crystalline-to-amorphous transformation, as determined from the evolution of the integrated peak intensities as a function of fluence, reveal that La2Ti2O7 (track diameter, d ∼ 7.2 nm with 181Ta and 5.1 nm with 129Xe) is more susceptible to amorphization than Gd2Ti2O7 (d ∼ 6.2 nm with 181Ta and 4.6 nm with 129Xe). The radiation response of the two titanate compounds can be understood in the context of their different structures and cation ionic radius ratios rA/rB, where the susceptibility of radiation of titanate pyrochlores is proportionate with this radius ratio. The higher electronic linear energy loss of the 181Ta ions as compared with 129Xe ions leads to a consistent increase of volume amorphized per ion in both materials, which manifests as a larger track diameter.

PHASE TRANSITION IN LAYERED PEROVSKITE LIKE MANGANATE Ca3Mn2O7 UNDER HIGH PRESSURE

2001 ◽  
Vol 15 (18) ◽  
pp. 2491-2497 ◽  
Author(s):  
J. L. ZHU ◽  
L. C. CHEN ◽  
R. C. YU ◽  
F. Y. LI ◽  
J. LIU ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
The Other ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Diamond Anvil

In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca 3 Mn 2 O 7 under pressures up to 35 GPa have been performed by using diamond anvil cell with synchrotron radiation. The results show that the structure of layered perovskite-like manganate Ca 3 Mn 2 O 7 is unstable under pressure due to the easy compression of NaCl-type blocks. The structure of Ca 3 Mn 2 O 7 underwent two phase transitions under pressures in the range of 0~35 GPa. One was at about 1.3 GPa with the crystal structure changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic back to another tetragonal.

Adsorption behavior of samarium(III) from aqueous solutions onto PAN@SDS core-shell polymeric adsorbent

2015 ◽  
Vol 103 (6) ◽  
Author(s):  
Mamdoh R. Mahmoud ◽  
Mohamed A. Soliman ◽  
Karam F. Allan
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Aqueous Solutions ◽  
Sodium Dodecyl ◽  
Adsorption Behavior ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Polymeric Adsorbent ◽  
X Ray ◽  
Radiation Induced ◽  
Ft Ir

AbstractAdsorption behavior of samarium(III) radionuclides from aqueous solutions onto a novel polyacrylonitrile coated with sodium dodecyl sulfate (PAN@SDS), prepared by gamma radiation-induced polymerization, was studied in this work. The developed polymeric adsorbent was characterized by FT-IR, X-ray diffraction and N

scholarly journals Visualizing mineralization processes and fossil anatomy using synchronous synchrotron X-ray fluorescence and X-ray diffraction mapping

2020 ◽  
Vol 17 (169) ◽  
pp. 20200216 ◽  
Author(s):  
Pierre Gueriau ◽  
Solenn Réguer ◽  
Nicolas Leclercq ◽  
Camila Cupello ◽  
Paulo M. Brito ◽  
...  
Keyword(s):  
Cross Sections ◽  
Soft Tissues ◽  
Local Strain ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Transmission Geometry ◽  
Mineralization Processes ◽  
Elemental Data

Fossils, including those that occasionally preserve decay-prone soft tissues, are mostly made of minerals. Accessing their chemical composition provides unique insight into their past biology and/or the mechanisms by which they preserve, leading to a series of developments in chemical and elemental imaging. However, the mineral composition of fossils, particularly where soft tissues are preserved, is often only inferred indirectly from elemental data, while X-ray diffraction that specifically provides phase identification received little attention. Here, we show the use of synchrotron radiation to generate not only X-ray fluorescence elemental maps of a fossil, but also mineralogical maps in transmission geometry using a two-dimensional area detector placed behind the fossil. This innovative approach was applied to millimetre-thick cross-sections prepared through three-dimensionally preserved fossils, as well as to compressed fossils. It identifies and maps mineral phases and their distribution at the microscale over centimetre-sized areas, benefitting from the elemental information collected synchronously, and further informs on texture (preferential orientation), crystallite size and local strain. Probing such crystallographic information is instrumental in defining mineralization sequences, reconstructing the fossilization environment and constraining preservation biases. Similarly, this approach could potentially provide new knowledge on other (bio)mineralization processes in environmental sciences. We also illustrate that mineralogical contrasts between fossil tissues and/or the encasing sedimentary matrix can be used to visualize hidden anatomies in fossils.

Study on the phase structure and mechanical properties of (Ti,Al,Si)N coatings deposited by multiarc ion plating

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040043
Author(s):  
Mengchao Wang ◽  
Lijun Wang ◽  
Hui Chen ◽  
Yinfen Cheng
Keyword(s):  
Cross Sections ◽  
Phase Structure ◽  
Structural Formula ◽  
Columnar Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ion Plating ◽  
Substrate Adhesion ◽  
Scratch Tests ◽  
Angular Shift

Different structural [Formula: see text] coatings were designed and deposited on WC-Co cemented carbide by the technology of multiarc ion plating. Monolayered [Formula: see text] coating was deposited using cathode of [Formula: see text]. Multilayered (Ti,Al)N/[Formula: see text] coating and [Formula: see text] coating with gradual silicon content were deposited using two cathodes of [Formula: see text] and [Formula: see text] simultaneously. The surface and cross-section morphology, compositions, and phase structure were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The dense [Formula: see text] coatings with droplets on the surface and without obvious columnar structure on the cross-sections were obtained. All coatings had the strong peaks of (200) orientation. The different angular shift occurred with different combination of cathodes and processes. The introduction of multilayered and gradient structure effectively reduced the lattice distortion of coatings. Meanwhile, the coating-substrate adhesion strength increased from 38.57 N to 60.17 N with a coating thickness of approximately 3.5 [Formula: see text]m by scratch tests. The highest hardness of [Formula: see text] coating obtained in this paper were [Formula: see text] GPa by nanoindentation. The multilayered coating showed better toughness.

Effects of CaB2O4 Content on the Sintering Behavior of Hexagonal Boron Nitride

2011 ◽  
Vol 675-677 ◽  
pp. 131-134
Author(s):  
Yu Xia Cao ◽  
Ling Zhong Du ◽  
Wei Gang Zhang
Keyword(s):  
Boron Nitride ◽  
Diffraction Analysis ◽  
Apparent Density ◽  
Cross Sections ◽  
Hexagonal Boron Nitride ◽  
Sintering Behavior ◽  
Rockwell Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes

CaB2O4 was added into hexagonal boron nitride (hBN) to improve the sintering behaviors of hBN. CaB2O4 and hBN were mixed and then pressed into plates. The plates were sintered at 2000°C for 5h under a N2 ambience. The phase compositions with different CaB2O4 contents were examined with X-ray diffraction analysis. The fracture cross-sections of the hBN plates were investigated by SEM. The apparent density and Rockwell hardness were also measured. The results show that the hBN particles had a plate-like shape and the grain sizes of hBN increased with increasing CaB2O4 contents. The apparent density and Rockwell hardness decreased with increasing CaB2O4 contents. When the CaB2O4 content was 15(wt) %, the hBN has the average grain sizes of 3μm in diameter and 200nm in thickness, the apparent density of 1.06 g/cm3 and the Rockwell hardness of 3, respectively.

Structural Modifications in Thin Films Caused by Gamma Radiation

2005 ◽  
Vol 480-481 ◽  
pp. 13-20 ◽  
Author(s):  
Khalil Arshak ◽  
Olga Korostynska ◽  
John Henry
Keyword(s):  
Thin Films ◽  
Gamma Radiation ◽  
Structural Changes ◽  
X Ray Diffraction ◽  
Thermal Vacuum ◽  
X Ray ◽  
Structural Modifications ◽  
Thin Oxide Films ◽  
Radiation Induced ◽  
Induced Changes

This paper reports on the gamma radiation-induced changes in thin oxide films deposited by thermal vacuum technique. Structures of various oxides thin films, such as In2O3, SiO and TeO2 and their mixtures in different proportions were studied. The influence of gamma radiation on In2O3/SiO films has resulted in significant changes in the microstructure of this film. Some kind of agglomerations with variable sizes in the range 0.5-3 µm has occurred. After a dose of 8160 µSv an evidence of partial crystallisation was observed with X-ray diffraction. Structural changes in TeO2 thin film were explored by means of Raman spectroscopy. After they have been exposed to g- radiation, a strong peak appeared at 448.83 cm-1, indicating further transformation to g-TeO2 modification.

Sign in / Sign up

Export Citation Format

Share Document