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2 edition of Oxidation and deformation studies of uranium nitride by electron microscopy found in the catalog.

Oxidation and deformation studies of uranium nitride by electron microscopy

Michael John Sole

Oxidation and deformation studies of uranium nitride by electron microscopy

by Michael John Sole

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  • 2 Currently reading

Published by Atomic Energy Board in Pelindaba .
Written in English

    Subjects:
  • Uranium nitride.,
  • Electrons -- Diffraction.,
  • Electron microscopy.

  • Edition Notes

    Statementby M. J. Sole and C. M. van der Walt.
    ContributionsVan Der Walt, C. M., joint author., South Africa. Atomic Energy Board.
    Classifications
    LC ClassificationsDA615 .T3 1967
    The Physical Object
    Pagination11 l.
    Number of Pages11
    ID Numbers
    Open LibraryOL5577505M
    LC Control Number67089840

    This work demonstrates that the oxidation state and chemistry of uranium hydrides can be tuned with temperature and the stoichiometry of phenylsilane. The trivalent uranium hydride [(C5Me5)2U–H]x (5) was found to be comprised of an equilibrium mixture of U(III) hydrides in solution at ambient temperature. A single U(III) species can be selectively prepared by treating (C5Me5)2UMe2 (4) with 2.   Relativistic study of xenotime, YPO$_4$, containing atoms thorium and uranium as point defects is performed in the framework of cluster model with using the compound-tunable embedding potential (CTEP) method proposed by us recently. The Y-(PO$_4$)$_6$-Y'$_{22}$-O'$_{}$ cluster for xenotime is considered, in which central part, [Y-(PO$_4$)$_6$]$^{}$, is the main cluster, whereas .

      In contrast to a wealth of terminal d-block nitrides,[] the uranium nitride bond was, until recently,[] prominent by its absence outside of spectroscopic studies.[] Molecular uranium nitrides prepared on a large scale exhibited nitrides bridging two to four metal ions, were protected by a covalently bound borane, or decomposed by ligand C=H activation when generated by photolysis.[]. Low-temperature alteration reactions on uranium phases may lead to the mobilization of uranium and thereby poses a potential threat to humans living close to uranium-contaminated sites. In this study, the surface alteration of uraninite (UO2) and uranium tetrachloride (UCl4) in air atmosphere was studied by confocal laser scanning microscopy (CLSM) and laser-induced fluorescence spectroscopy.

      Uranium nitrides are among the most promising fuels for Generation IV nuclear reactors, but until now, very little has been known about their thermal stability properties under nonequilibrium conditions. In this work, thermal decomposition of nitrogen-rich uranium nitride (denoted as UN2–x) under ultrahigh-vacuum (UHV) conditions was investigated by thermal desorption spectroscopy (TDS). Abstract. Two methods are proposed to increase the oxidation resistance of uranium nitride (UN) nuclear fuel. These paths are: (1) Addition of USi{sub x} (e.g. U3Si2) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with various compounds (followed by densification via Spark Plasma Sintering or Liquid Phase Sintering) that will greatly increase oxidation.


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Oxidation and deformation studies of uranium nitride by electron microscopy by Michael John Sole Download PDF EPUB FB2

Oxidation and deformation studies of uranium nitride by electron microscopy Transmission electron microscopy and electron diffraction techniques have been used to study the oxidation and deformation of UN single crystals.

The initial oxidation product is epitaxial U 2 N 3+x which may contain ordered oxygen atoms. As oxidation proceeds a Cited by: OXIDATION AND DEFORMATION STUDIES OF URANIUM NITRIDE BY ELECTRON MICROSCOPY* M.

SOLE-)- and C. VAN DER WALT-j- Transmission electron microscopy and electron diffraction techniques have been used to study the oxidation and deformation of UN single by: Oxidation and deformation studies of uranium nitride by electron microscopy.

Article. and electron diffraction techniques have been used to study the oxidation and deformation of UN single. The oxidation kinetics of uranium surfaces modified by pulsed laser nitriding in air at temperatures of, and K has been investigated.

X-ray diffraction (XRD), Auger electron spectroscopy (AES) and scanning electron microscopy (SEM) were used to characterize the structure, morphology and composition of the by: 1.

Uranium nitride is any of a family of several ceramic materials: uranium mononitride (UN), uranium sesquinitride (U 2 N 3) and uranium dinitride (UN 2).The word nitride refers to the −3 oxidation state of the nitrogen bound to the uranium.

Uranium nitride has been considered as a potential fuel for nuclear reactors. It is said to be safer, stronger, denser, more thermally conductive and Chemical formula: U₂N₃. Transmission electron microscopy and electron diffraction techniques have been used to study the oxidation and deformation of UN single crystals.

The initial oxidation product is epitaxial U2N3+x. The initial oxidation processes of uranium nitride films were investigated in an ultra-high vacuum chamber of Auger electron spectroscopy. After L oxygen exposure, the oxide layer of UO 2 were formed on the surface of U, and UNUN films formed UO 2 with little UN x O y, while the UN film generated UN x O y oxide layer.

The experimental results confirmed that the nitrogen content determines the different oxidation behavior characteristics, that is, for pure uranium and low nitrogen content of uranium nitride, the oxide layer of UO 2 was formed on the surface of U, UN or UN film, while the UN film generated a ternary compound UN x O y.

The oxidative ammonolysis route was used to synthesize three uranium nitrides, UN2, U2N3, and UN, using UF4 as the starting material. Powder XRD analysis showed the UN2 and U2N3 products to contain less than wt % uranium oxides. UO2 level was identified to be (0) wt % in the UN product as it is made, but this level increases upon exposure to air.

The morphology of these nitrides was. Book. Jan ; Prof. Ludwig Reimer Oxidation and deformation studies of uranium nitride by electron microscopy. and electron diffraction techniques have been used to study the. Uranium is a chemical element with atomic number 92 which means there are 92 protons and 92 electrons in the atomic chemical symbol for Uranium is U.

Electron Configuration and Oxidation States of Uranium. Electron configuration of Uranium is [Rn] 5f3 6d1 7s2. Possible oxidation states are +3,4,5,6. Electron Configuration. Auger electron spectroscopy has been used to study the surface oxidation of a uranium niobium alloy, U 6 wt.% Nb, in a UHV environment containing primarily H2, H2O and CO.

McGillivray, G. W., Geeson, D. & Greenwood, R. Studies of the kinetics and mechanism of the oxidation of uranium by dry and moist air–A model for determining the oxidation. In order to synthesize nuclear fuel containing high loading of uranium, research in developing uranium nitride (UN) from uranium metal has been conducted by reacting the massive uranium metal with hydrogen gas at a temperature of K followed by dehydriding at a temperature of K under vacuum pressure and nitriding at a temperature of   This paper considers the results of applying of scanning electron microscopes in the backscattered electron mode for the specifying of the contents of multielemental samples and minerals, which are presented in publications.

This approach is used for estimation of oxidation state of uranium in microparticles. The possibility of this goal achieving is demonstrated on the example of the analysis. Since the earliest studies, back in the s, many methods of obtaining the nitrides have been developed, such as: direct nitriding, hydriding–dehydriding–nitriding, carbothermic nitriding, oxidative ammonolysis, and others [13, 14].

An overview of uranium nitride papers published through the years, from to is shown in Fig. A terminal uranium(VI)–nitride has been shown to be accessible and isolable by a redox strategy whereas a photochemical approach resulted in decomposition.

Computational analyses suggest that. After its use, spent uranium dioxide may be stored in containers, but one worry is that UO 2 will oxidize into mixed oxides, such as U 4 O 9 and U 3 O 8, which have more than one oxidation state.

These uranium oxide reactions, which can lead to environmental contamination, are not well characterized because of ambiguities in previous studies. Uranium is best known for its radioactivity. From the standpoint of lower-energy chemistry, uranium is also intriguing for its bonding motifs, which involve trinodal f orbitals.

King et al. [][1], published online 28 June; see the Perspective by [ Sattelberger and Johnson ][2]) synthesized and isolated a molecule bearing a uranium-nitrogen triple bond. Initial oxidation behaviors of nitride surfaces of uranium by XPS analysis. Applied Surface Science, DOI: / M.

Bonato, K. Ragnarsdottir, G. Allen. Removal of Uranium(VI), Lead(II) at the Surface of TiO2 Nanotubes Studied by X-Ray Photoelectron Spectroscopy.

All of the proposed uranium peaks were shown to shift to a lower kinetic energy with oxidation, indicating the potential for extracting chemical state information with Auger uranium studies.

The main molybdenum peak (Mo MNN) at eV was not resolved in the spectra because of the presence of the U N 6 O 4 O 5 peak with a similar kinetic energy.Uranium nitride.

Uranium nitride (UN) DTXSID Molecular Weight: g/mol. Dates: Modify: Create: Contents. 1 Structures Expand this section.

2 Names and Identifiers Expand this section. 3 Chemical and Physical Properties Expand this section.Calculation studies on the effect of carbon and oxygen impurities on the chemical and phase compositions of nitride uranium–plutonium fuel in the course of burnup are performed using the IVTANTHERMO code.

It is shown that the number of moles of UN decreases with increasing burnup level, whereas UN{sub }, UN{sub }, and UN{sub