Exposure tests of copper foils in a slurries of different bentonites

Abstract Materials for storing nuclear waste are a hot topic all over the globe right now. This study monitors corrosion behaviour of copper as one of the contemplated materials in the Czech bentonite Rokle B75. The tests were carried out in a thermostated cell deaerated with argon at temperatures of 90 and 40°C in the environment of bentonite pore solution, bentonite pore solution with an addition of sulphides and wet bentonite suspension. The scanning electron microscopy, X-ray diffraction, Raman spectroscopy, electrochemical impedance spectroscopy and resistometric methods of corrosion rate measurements were applied. The most compact layer is formed in the environment of bentonite pore solution. The addition of sulphides leads to a significant growth of thickness of the layer of corrosion products and its porosity. However, the porosity decreases towards the layer - metal interface. The layer formed after exposure to the wet bentonite suspension is reported to have the worst parameters. Nevertheless, considering the final temperature of 40°C in the repository, the corrosion rate will still be acceptable.

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Defect-Mediated Conductivity Enhancements in Na3-xPn1-xWxS4 (Pn = P, Sb) using Aliovalent Substitutions

10.26434/chemrxiv.9943961.v2 ◽

2019 ◽

Author(s):

Till Fuchs ◽

Sean Culver ◽

Paul Till ◽

Wolfgang Zeier

Keyword(s):

Ionic Conductivity ◽

Vacancy Concentration ◽

Sodium Ion ◽

High Ionic Conductivity ◽

Ionic Conductors ◽

X Ray Diffraction ◽

X Ray ◽

Solid State Batteries ◽

Ion Conducting ◽

Very High

The sodium-ion conducting family of Na3PnS4, with Pn = P, Sb, have gained interest for the use in solid-state batteries due to their high ionic conductivity. However, significant improvements to the conductivity have been hampered by the lack of aliovalent dopants that can introduce vacancies into the structure. Inspired by the need for vacancy introduction into Na3PnS4, the solid solutions with WS42- introduction are explored. The influence of the substitution with WS42- for PS43- and SbS43-, respectively, is monitored using a combination of X-ray diffraction, Raman and impedance spectroscopy. With increasing vacancy concentration improvements resulting in a very high ionic conductivity of 13 ± 3 mS·cm-1 for Na2.9P0.9W0.1S4 and 41 ± 8 mS·cm-1 for Na2.9Sb0.9W0.1S4 can be observed. This work acts as a stepping-stone towards further engineering of ionic conductors using vacancy-injection via aliovalent substituents.

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Defect-Mediated Conductivity Enhancements in Na3-xPn1-xWxS4 (Pn = P, Sb) using Aliovalent Substitutions

10.26434/chemrxiv.9943961.v1 ◽

2019 ◽

Author(s):

Till Fuchs ◽

Sean Culver ◽

Paul Till ◽

Wolfgang Zeier

Keyword(s):

Ionic Conductivity ◽

Vacancy Concentration ◽

Sodium Ion ◽

High Ionic Conductivity ◽

Ionic Conductors ◽

X Ray Diffraction ◽

X Ray ◽

Solid State Batteries ◽

Ion Conducting ◽

Very High

The sodium-ion conducting family of Na3PnS4, with Pn = P, Sb, have gained interest for the use in solid-state batteries due to their high ionic conductivity. However, significant improvements to the conductivity have been hampered by the lack of aliovalent dopants that can introduce vacancies into the structure. Inspired by the need for vacancy introduction into Na3PnS4, the solid solutions with WS42- introduction are explored. The influence of the substitution with WS42- for PS43- and SbS43-, respectively, is monitored using a combination of X-ray diffraction, Raman and impedance spectroscopy. With increasing vacancy concentration improvements resulting in a very high ionic conductivity of 13 ± 3 mS·cm-1 for Na2.9P0.9W0.1S4 and 41 ± 8 mS·cm-1 for Na2.9Sb0.9W0.1S4 can be observed. This work acts as a stepping-stone towards further engineering of ionic conductors using vacancy-injection via aliovalent substituents.

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High-Temperature Corrosion Performance of FeAl-Based Alloys Containing Carbon in Molten Salt

Metals ◽

10.3390/met11122040 ◽

2021 ◽

Vol 11 (12) ◽

pp. 2040

Author(s):

Munish Kumar ◽

Ravi Kant ◽

Suresh Chand ◽

Ujjwal Prakash ◽

Shankar Sehgal ◽

...

Keyword(s):

Corrosion Behavior ◽

Molten Salts ◽

Corrosion Performance ◽

X Ray Diffraction ◽

Corrosive Media ◽

Al2o3 Layer ◽

X Ray ◽

Aggressive Environment ◽

Arc Melting ◽

Ti Addition

Corrosion behavior of FeAl-based alloys containing carbon produced through arc melting in argon atmosphere has been studied at 500 °C to 700 °C. The samples were tested in the aggressive environment of molten salts (80%V2O5/20%Na2SO4). The corrosion behavior was observed by weight change method and the layer products formed were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The different phase components were observed in the surface layer after the test in Fe-22Al alloy. A protective Al2O3 layer was confirmed for Fe-22Al alloy containing carbon only. However, an additional TiO layer was also observed in Fe-22Al alloy containing carbon with Ti addition. The microstructural and XRD examinations revealed that this additional TiO layer protects better against penetration of corrosive media. The corrosion resistance behavior of FeAl-based alloys were addressed on the basis of microstructural evidence.

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Early Palaeolithic bone diagenesis in the Arago cave at Tautavel, France

Mineralogical Magazine ◽

10.1180/002646199548943 ◽

1999 ◽

Vol 63 (6) ◽

pp. 801-812 ◽

Cited By ~ 27

Author(s):

L. Quattropani ◽

L. Charlet ◽

H. de Lumley ◽

M. Menu

Keyword(s):

Clay Minerals ◽

Gamma Ray ◽

Trace Element Composition ◽

Element Composition ◽

X Ray Diffraction ◽

Human Occupation ◽

X Ray ◽

Bone Diagenesis ◽

Very High ◽

P Influx

AbstractBones from level G in the Arago cave (Tautavel, Southern France, 450 ky) were analysed using a combination of particle induced X-ray and gamma-ray emission (PIXE and PIGME) and X-ray diffraction (XRD). Human occupation and guano production by bats introduced a large amount of phosphate into the cave and as a result a decarbonated pocket was formed in the sediment, characterized by the dissolution of clay minerals, calcite and bones, and by the precipitation of phosphate secondary minerals. The Al released by clay minerals was reprecipitated as crandallite in the few remaining bones, and as montgomeryite with traces of crandallite in the surrounding sediments. Bones within the pocket have very high levels of Al, Fe, F and Zn and often have ‘diffusive’ type U-shaped concentration profiles. These profiles show that post-mortem uptake of trace elements occurred, and thus that trace element composition has to be used with care in palaeonutritional studies but is indicative of local palaeoenvironment. This uptake is complicated by a large increase in hydroxylapatite crystallinity in Palaeolithic bones compared to modern or more recent ones, as a result of the large P influx which occurred in the Arago cave after the sediment deposition.

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Investigation of Magnetic Order in Iron Oxide-Nickel Oxide Superlattices with Modulation Wavelength Less Than 80 Å

MRS Proceedings ◽

10.1557/proc-231-423 ◽

1991 ◽

Vol 231 ◽

Author(s):

S. D. Berry ◽

D. M. Lind ◽

G. Chern ◽

H. Mathias ◽

L. R. Testardi

Keyword(s):

Magnetic Order ◽

Spontaneous Magnetization ◽

X Ray Diffraction ◽

High Crystalline Quality ◽

X Ray ◽

Long Wavelength ◽

Saturation Moment ◽

Very High ◽

Modulation Wavelength

AbstractWe have investigated the magnetic order, using SQUID magnetometry, for short modulation wavelength Fe3O4/NiO superlattices, grown on single crystal MgO. Ferrimagnetic Fe3O4 has a saturation moment of ~500 emu/cm3 at 0 K and a Curie temperature of 858 K, while bulk NiO is antiferromagnetic with a NMel temperature of 525 K. Very high crystalline quality with little interdiffusion is indicated by X-ray diffraction, SEM, optical microscopy, and in-situ RHEED, and the samples show highly anisotropic electrical conductivity which also indicates the strong modulation present. Long wavelength samples (Amod > 200 Å) have a behavior only slightly different from that expected from bulk Fe3O4, but for Amod<80 Å, spontaneous magnetization is replaced by paramagnetism, with weak temperature dependence (not I/T) from 5 K to 400 K.

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Phase Transformation of Powdered Material by Using Metal Jet

Materials Science Forum ◽

10.4028/www.scientific.net/msf.706-709.741 ◽

2012 ◽

Vol 706-709 ◽

pp. 741-744 ◽

Cited By ~ 1

Author(s):

Akio Kira ◽

Ryuichi Tomoshige ◽

Kazuyuki Hokamoto ◽

Masahiro Fujita

Keyword(s):

Phase Transformation ◽

Powdered Material ◽

Scanning Transmission Electron Microscope ◽

Ultrahigh Pressure ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Scanning Transmission ◽

Metal Jet ◽

Very High

The various techniques of phase transformation of the material have been proposed by many researchers. We have developed several devices to generate the ultrahigh pressure by using high explosive. One of them uses metal jets. It is expected that the ultrahigh pressure occurs by the head-on collision between metal jets, because the velocity of the metal jet is very high. By mixing a powdered material with metal jets, the pressure of the material becomes high. The purpose of this study is to transform the phase of the powdered material by using this high pressure. The powders of the graphite and hBN were applied. The synthesis to the diamond and cBN was confirmed by X-ray diffraction (XRD). In this paper, the mechanism of the generation of the ultrahigh pressure is explained and the results of the observation of the powder by using scanning transmission electron microscope (STEM) are reported.

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X‐Ray Diffraction Studies on Liquids at Very High Pressures along the Melting Curve II. Sodium

The Journal of Chemical Physics ◽

10.1063/1.1678524 ◽

1972 ◽

Vol 57 (5) ◽

pp. 2016-2021 ◽

Cited By ~ 20

Author(s):

Keith H. Brown ◽

J. Dean Barnett

Keyword(s):

High Pressures ◽

Melting Curve ◽

X Ray Diffraction ◽

X Ray ◽

Very High

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X-Ray Reflectivity Studies of Pt/AlN Multilayered Films

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.2095 ◽

2007 ◽

Vol 561-565 ◽

pp. 2095-2098

Author(s):

Takashi Harumoto ◽

Ji Shi ◽

Yoshio Nakamura

Keyword(s):

Layer Structure ◽

Bragg Reflection ◽

X Ray Diffraction ◽

Multilayered Films ◽

Sputtering Deposition ◽

X Ray ◽

First Order ◽

Periodic Layer ◽

Deposited Films ◽

Very High

Pt/AlN multilayered films fabricated by alternative sputtering deposition were characterized by X-Ray Reflectometry and X-Ray Diffraction. As-deposited films have (111) and (001) preferred orientation for Pt and AlN, respectively. The X-Ray Reflectivity profiles are assigned to the total reflection and Bragg reflections due to periodic layer structure. The Bragg peaks are observed at the 2Theta range beyond 15 degree and the peak intensities increase after annealing. The reflectivity of the first order Bragg reflection is approximately 65% and is stable after annealing at 873K. Simulation of the reflectivity profile has shown roughnesses of the Pt/AlN interfaces are below 0.4nm. X-Ray Diffraction revealed the development of film texture and formation of superlattice by annealing. The latter indicates periodicity of film is very high.

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