Oxidation of Alloy-X in Subcritical, Transition, and Supercritical Water

CORROSION ◽  
10.5006/3881 ◽  
2021 ◽  
Author(s):  
Zachary Karmiol ◽  
Dev Chidambaram
Keyword(s):  
Supercritical Water ◽  
Photoelectron Spectroscopy ◽  
Focused Ion Beam ◽  
Elevated Temperatures ◽  
Subcritical Water ◽  
Ion Beam ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nickel Based Superalloy ◽  
Before And After

This work investigates the oxidation of a nickel based superalloy, namely Alloy X, in water at elevated temperatures: subcritical water at 261°C and 27 MPa, the transition between subcritical and supercritical water at 374°C and 27 MPa, and supercritical water at 380°C and 27 MPa for 100 hours. The morphology of the sample surfaces were studied using scanning electron microscopy coupled with focused ion beam milling, and the surface chemistry was investigated using X-ray diffraction, Raman spectroscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy before and after exposure studies. Surfaces of all samples were identified to comprise of a ferrite spinel containing aluminum.

Characterization of X-ray irradiated graphene oxide coatings using X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy

2013 ◽  
Vol 28 (2) ◽  
pp. 68-71 ◽  
Author(s):  
Thomas N. Blanton ◽  
Debasis Majumdar
Keyword(s):  
Atomic Force Microscopy ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
X Ray Diffraction ◽  
Carbon Phase ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.

A study of adsorption and absorption mechanisms of copper in palygorskite

Clay Minerals ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 195-203 ◽  
Author(s):  
Y. F. Cai ◽  
J. Y. Xue
Keyword(s):  
Photoelectron Spectroscopy ◽  
Esr Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tetrahedral Sites ◽  
Octahedral Cation ◽  
Spin Resonance ◽  
Before And After ◽  
Cu Ions ◽  
Complex Ion

AbstractDesorption experiments performed on four Cu-adsorbed palygorskites suggest that the leached Cu2+ ion originates at the surface and/or net-like interstice of the palygorskite fibres. The leached fraction, calculated from the quantities of adsorbed Cu2+ before and after desorption, is <1%. This may indicate that the majority of Cu is in inaccessible structural sites. X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared (FTIR) spectroscopy and electron spin resonance (ESR) were used to determine the mineralogical character of the Cu-adsorbed palygorskite. Two photoelectron lines at 932.5 and/or 933.7 eV in the narrow scan Cu 2p3/2 spectra show that Cu adsorbed on the surface of palygorskite is in the Cu+ and Cu2+ state. The stretching vibrations of the octahedral cation shift ~3–5 cm–1 towards a greater wavenumber in the FTIR spectra of Cu-adsorbed palygorskite. It can be deduced that the Cu2+ is trapped in the channel of the palygorskite structure. The ESR spectra of the palygorskite give g values of 2.34, 2.12, 2.08 and 2.05, suggesting that some Cu ions cannot be reached by H+. These results confirm that Cu is adsorbed by palygorskite via three possible mechanisms: (1) the Cu is adsorbed onto the surface or in a net-like interstice, and its oxidation states are +1 and +2; (2) Cu forms a complex ion – [Cu(H2O)4]2+ or [Cu(H2O)6]2+, and is trapped in the channel; or (3) Cu enters into the hexagonal channel of the tetrahedral sites or the unoccupied octahedral sites of palygorskite.

The Nc State Analytical Instrumentation Facility

1999 ◽  
Vol 5 (S2) ◽  
pp. 10-11
Author(s):  
J.R. Phillips ◽  
D.P. Griffis ◽  
P.E. Russell
Keyword(s):  
Surface Science ◽  
Photoelectron Spectroscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Non Profit ◽  
X Ray ◽  
Industrial Organizations ◽  
Extensive Collection ◽  
Analytical Instrumentation ◽  
Analytical Services

The Analytical Instrumentation Facility (AIF) is a laboratory composed of scientists and engineers specializing in the development and application of advanced techniques for materials characterization (http://spm.aif.ncsu.edu/aif/index.html)http://www.nice.org.uk/page.aspx?o=43210. AIF facilities include an extensive collection of analytical instrumentation utilized in teaching, research, and in support of academic and industrial programs. General forms of analysis include: electron, ion, and photon microscopies, surface science and analysis, and scanned probe microscopies. An abbreviated listing of AIF capabilities follows: metallography/sample preparation, optical microscopy, X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Secondary Ion Mass Spectroscopy (SIMS), Secondary Electron Microscopy (SEM), Scanned Probe Microscopy (SPM), Micro-Raman Spectroscopy, Focused Ion Beam Micro-machining (FIBM), Auger Electron Spectroscopy (AES), and X-Ray Photoelectron Spectroscopy (XPS or ESCA).AIF is a resource utilized not only by those within NC State requiring analytical services, but also by a large number of North Carolina non-profit and industrial organizations as well as the Materials Community at large.

scholarly journals Influence of Activator Na2O Concentration on Residual Strengths of Alkali-Activated Slag Mortar upon Exposure to Elevated Temperatures

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1296 ◽  
Author(s):  
Tai Tran ◽  
Hyug-Moon Kwon
Keyword(s):  
Thermogravimetric Analysis ◽  
Elevated Temperatures ◽  
Silicate Liquid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strength Variation ◽  
Before And After ◽  
Activated Slag ◽  
Alkali Activated ◽  
Slag Weight

The mechanical strength variation of ambient cured Alkali-activated mortar (AAS) upon exposure to elevated temperatures from 200 to 1200 °C was studied in this article. Slag was activated by the combination of sodium silicate liquid (Na2SiO3) and sodium hydroxide (NaOH) with different Na2O concentrations of 4%, 6%, 8%, and 10% by slag weight. Mechanical properties comprising compressive strength, flexural strength, and tensile strength before and after exposure were measured. Thermogravimetric analysis (Thermogravimetric analysis (TGA) and Derivative thermogravimetric (DTG)), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDS) were also used for strength alteration explanation. The results indicated that Na2O concentration influence on strength variation of AAS mortar was observed clearly at temperature range from ambient temperature to 200 °C. The melting alteration of AAS mortar after exposed to 1200 °C was highly dependent on concentrations of Na2O.

X-ray Photoelectron Spectroscopy (XPS) Investigation of the Surface Film on Magnesium Powders

2012 ◽  
Vol 66 (5) ◽  
pp. 510-518 ◽  
Author(s):  
Paul J. Burke ◽  
Zeynel Bayindir ◽  
Georges J. Kipouros
Keyword(s):  
Surface Layer ◽  
Photoelectron Spectroscopy ◽  
Focused Ion Beam ◽  
Surface Film ◽  
Ion Beam ◽  
Pure Magnesium ◽  
Atmospheric Conditions ◽  
Magnesium Powder ◽  
X Ray ◽  
Aerospace Applications

Magnesium (Mg) and its alloys are attractive for use in automotive and aerospace applications because of their low density and good mechanical properties. However, difficulty in forming magnesium and the limited number of available commercial alloys limit their use. Powder metallurgy may be a suitable solution for forming near-net-shape parts. However, sintering pure magnesium presents difficulties due to surface film that forms on the magnesium powder particles. The present work investigates the composition of the surface film that forms on the surface of pure magnesium powders exposed to atmospheric conditions and on pure magnesium powders after compaction under uniaxial pressing at a pressure of 500 MPa and sintering under argon at 600 °C for 40 minutes. Initially, focused ion beam microscopy was utilized to determine the thickness of the surface layer of the magnesium powder and found it to be ∼10 nm. The X-ray photoelectron analysis of the green magnesium sample prior to sintering confirmed the presence of MgO, MgCO3·3H2O, and Mg(OH)2 in the surface layer of the powder with a core of pure magnesium. The outer portion of the surface layer was found to contain MgCO3·3H2O and Mg(OH)2, while the inner portion of the layer is primarily MgO. After sintering, the MgCO3·3H2O was found to be almost completely absent, and the amount of Mg(OH)2 was also decreased significantly. This is postulated to occur by decomposition of the compounds to MgO and gases during the high temperature of sintering. An increase in the MgO content after sintering supports this theory.

scholarly journals Annealing of focused ion beam damage in gold microcrystals: an in situ Bragg coherent X-ray diffraction imaging study

2021 ◽  
Vol 28 (2) ◽  
pp. 550-565 ◽  
Author(s):  
David Yang ◽  
Nicholas W. Phillips ◽  
Kay Song ◽  
Ross J. Harder ◽  
Wonsuk Cha ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Imaging Study ◽  
X Ray Diffraction ◽  
Multiple Reflections ◽  
X Ray ◽  
Self Diffusion ◽  
Diffraction Imaging ◽  
Gold Microcrystals

Focused ion beam (FIB) techniques are commonly used to machine, analyse and image materials at the micro- and nanoscale. However, FIB modifies the integrity of the sample by creating defects that cause lattice distortions. Methods have been developed to reduce FIB-induced strain; however, these protocols need to be evaluated for their effectiveness. Here, non-destructive Bragg coherent X-ray diffraction imaging is used to study the in situ annealing of FIB-milled gold microcrystals. Two non-collinear reflections are simultaneously measured for two different crystals during a single annealing cycle, demonstrating the ability to reliably track the location of multiple Bragg peaks during thermal annealing. The thermal lattice expansion of each crystal is used to calculate the local temperature. This is compared with thermocouple readings, which are shown to be substantially affected by thermal resistance. To evaluate the annealing process, each reflection is analysed by considering facet area evolution, cross-correlation maps of the displacement field and binarized morphology, and average strain plots. The crystal's strain and morphology evolve with increasing temperature, which is likely to be caused by the diffusion of gallium in gold below ∼280°C and the self-diffusion of gold above ∼280°C. The majority of FIB-induced strains are removed by 380–410°C, depending on which reflection is being considered. These observations highlight the importance of measuring multiple reflections to unambiguously interpret material behaviour.

scholarly journals Copper Corrosion in Aqueous Sulfide Solutions under Nuclear Waste Repository Conditions

2012 ◽  
Vol 1475 ◽  
Author(s):  
J. Chen ◽  
Z. Qin ◽  
D. W. Shoesmith
Keyword(s):  
Nuclear Waste ◽  
Photoelectron Spectroscopy ◽  
Focused Ion Beam ◽  
Film Growth ◽  
Electrochemical Impedance ◽  
Ion Beam ◽  
Chloride Content ◽  
Nuclear Waste Repository ◽  
Copper Corrosion ◽  
X Ray

ABSTRACTThe corrosion behavior of oxygen-free copper in anoxic sulfide solutions under nuclear waste disposal conditions was studied using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) equipped with a focused ion beam (FIB), X-ray photoelectron spectroscopy (XPS) and Micro X-ray diffraction (μXRD). The film growth process and mechanism were elucidated using an Au marker test, and the contribution of solution diffusion to corrosion was demonstrated in magnetically-stirred experiments. The effect of groundwater chemistry, particularly chloride content on copper corrosion and film properties was characterized using long-term corrosion experiments.

scholarly journals Sorption of Molybdates and Tungstates on Functionalized Montmorillonites: Structural and Textural Features

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2253 ◽  
Author(s):  
Magdalena Tuchowska ◽  
Barbara Muir ◽  
Mariola Kowalik ◽  
Robert P. Socha ◽  
Tomasz Bajda
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Inorganic Compounds ◽  
Ammonium Bromide ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Mineral Sorbent ◽  
Dimethyl Ammonium

Montmorillonite—the most popular mineral of the smectite group—has been recognized as a low-cost, easily available mineral sorbent of heavy metals and other organic and inorganic compounds that pollute water. The aim of this work was to determine the sorption mechanism and to identify the reaction products formed on the surface of montmorillonite and organo-montmorillonite after sorption of molybdates (Mo(VI)) and tungstates (W(VI)). Montmorillonites are often modified to generate a negative charge on the surface. The main objective of the study was to investigate and compare the features of Na-montmorillonite (Na-M), montmorillonite modified with dodecyl trimethyl ammonium bromide (DDTMA-M), and montmorillonite modified with didodecyl dimethyl ammonium bromide (DDDDMA-M) before and after sorption experiments. The material obtained after sorption was studied by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The XRD pattern showed the presence of a new crystallic phase in the sample that was observed under an SEM as an accumulation of crystals. The FTIR spectra showed bands related to Mo–O and W–O vibration (840 and 940 cm−1, respectively). The obtained results suggest that molybdenum(VI) and tungsten(VI) ions sorb onto the organo-montmorillonite in the form of alkylammonium molybdates and tungstates.

The Effect of Dopant Additions on the Microstructure of Boron Fibers Before and After Reaction to MgB2

2004 ◽  
Vol 848 ◽  
Author(s):  
James V. Marzik ◽  
Raymond J. Suplinskas ◽  
William J. Croft ◽  
Warren J. MoberlyChan ◽  
John D. DeFouw ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Elevated Temperatures ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Boron Fiber ◽  
Transmission Electron ◽  
Before And After ◽  
Fiber Metal ◽  
Molten Magnesium

ABSTRACTBoron fibers made by a commercial chemical vapor deposition (CVD) process have been used as precursors for the formation of magnesium diboride (MgB2) superconducting wires. Prior to a reaction with magnesium, the addition of dopants such as carbon and titanium to the boron fiber has been shown to enhance the superconducting properties of MgB2. These dopants also influence the kinetics of the reaction with magnesium. In this study, the effect of carbon dopant additions on the microstructure of boron fibers was investigated using powder x-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Additionally, bundles of boron fibers were pressure infiltrated with molten magnesium and reacted at elevated temperatures. The microstructure and microchemistry of the fiber-metal interfaces were investigated by TEM and energy dispersive x-ray analysis (EDS).

scholarly journals Initial Interaction of Crystalline Al/Amorphous Si Bilayer during Annealing

2004 ◽  
Vol 808 ◽  
Author(s):  
Yonghao Zhao ◽  
Jiangyong Wang ◽  
Eric J. Mittemeijer
Keyword(s):  
Auger Electron ◽  
Focused Ion Beam ◽  
Imaging Techniques ◽  
Ion Beam ◽  
X Ray Diffraction ◽  
X Ray ◽  
Initial Interaction ◽  
Magnetron Sputter ◽  
Amorphous Si ◽  
Sputter Deposited

ABSTRACTInitial interaction of a magnetron sputter deposited Al(100 nm, {111} fibre textured)/Si(150 nm, amorphous) bilayer, induced by isothermally annealing at 523 K for 60 min in a vacuum of 2.0×10−4 Pa, was studied by X-ray diffraction, Auger electron microscopy and focused-ion beam imaging techniques. Upon annealing, the crystalline Si had grown into the grain boundaries of the Al layer with a {111} texture, a crystallite size of approximate 12 nm and a tensile stress of +138 MPa. Simultaneously, the Al grains had grown into the Si layer from the original interface of the a-Si and Al sublayers with the lateral grain growth. The stress parallel to the surface of the Al layer had changed from +27 MPa to +232 MPa after annealing.

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