Measurement of Thin Oxide Surface Film Thicknesses and Atomic Densities by the Analysis of Positive Ion Excited Soft X-Ray Spectra

1969 ◽  
pp. 457-479
Author(s):  
W. P. Saylor ◽  
C. L. Marks
Keyword(s):  
Surface Film ◽  
Oxide Surface ◽  
X Ray ◽  
Thin Oxide ◽  
Positive Ion

Measurement of Thin Oxide Surface Film Thicknesses and Atomic Densities by the Analysis of Positive Ion Excited Soft X-Ray Spectral

1968 ◽  
Vol 12 ◽  
pp. 457-479 ◽  
Author(s):  
W. P. Saylor ◽  
C. L. Marks
Keyword(s):  
Thin Films ◽  
Surface Film ◽  
Target Material ◽  
High Sensitivity ◽  
Low Energy ◽  
Oxide Surface ◽  
Surface Films ◽  
Calibration Data ◽  
X Ray ◽  
Positive Ion

AbstractCharacteristic soft x-ray emission lines created as a result of low energy (10-100keV) positive ion excitation of a target material has been applied to the study of thin films of oxygen that form naturally on metal surfaces. The specific metals investigated were aluminum and nickel aa well as a number of their corresponding alloys.Low energy positive ions are well suited as projectiles for the study of thin films in that they have low penetrating powers, yet produce high x-ray yields for K-, L-, and M-shell elemental x-ray lines. Perhaps the most important feature is the fact that no background bremsstrahlung continuum x-radiation is generated in the slowing processes of the ions. Exploiting the advantages of these facts, a special high sensitivity detection technique has been developed for the soft x-ray analysis of the constituents that make up a particular thin surface film.The physical basis for thickness and atomic density measurements of thin surface films by positive ion excitation are discussed. Calibration data are presented for thin films of known thickness and composition establishing the sensitivity of the method for the measurement of the elemental atomic densities of thin films down to a few monolayers or approximately 10 Å in thickness. Finally, the results of the analysis of oxide surface films of aluminum, nickel and some of their alloys are presented and discussed.The objective of this continuing program is to gain an understanding of the mechanisms and principles governing the formation of oxide surface films on metals with the basic goal of producing new alloying techniques for metal passification in a saline environment.

scholarly journals Application of X-rays Diffraction for Identifying Thin Oxide Surface Layers on Zinc Coatings

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1005
Author(s):  
George Vourlias
Keyword(s):  
Grazing Incidence ◽  
Oxide Surface ◽  
Zinc Oxide Film ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thin Oxide Films ◽  
Thin Oxide ◽  
Predicted Values ◽  
Zinc Coatings

Structural characterization of compound material coatings is usually achieved using time-consuming and destructive techniques such as optical and electrical microscopy, which require the use of grinding processes not always compatible with the material. This paper reports on the effective use of a theoretical model based on X-ray diffraction to calculate the thickness and composition of thin oxide films formed on the surface of zinc coatings. Zinc coatings are widely used in industrial application as protective layers against the atmospheric corrosion of steel substrates. The thickness of single- and multi-layer coatings is estimated using grazing incidence X-ray diffraction and various incidence angles. The coatings were grown using hot-dip, pack cementation and thermal spray techniques, and their experimental characteristics were compared to the theoretically predicted values of thickness and composition. The results indicate the formation of a thin zinc oxide film on top of each coating, which acts as an isolation layer and protects the surface of the sample against the environmental corrosion. Finally, the penetration depth of the X-rays into the zinc-based coatings for grazing incidence and Bragg–Brentano X-ray diffraction geometries were calculated using theoretical equations and experimentally confirmed.

X-ray photoelectron spectroscopy study of the interaction of methanol with polycrystalline copper oxide surface

1996 ◽  
Vol 11 (7) ◽  
pp. 1605-1608 ◽  
Author(s):  
S. Badrinarayanan ◽  
A. B. Mandale ◽  
S. R. Sainkar
Keyword(s):  
Copper Oxide ◽  
Photoelectron Spectroscopy ◽  
Low Dose ◽  
Dissociative Adsorption ◽  
Methanol Decomposition ◽  
Oxide Surface ◽  
Polycrystalline Copper ◽  
Spectroscopy Study ◽  
Methanol Vapor ◽  
X Ray

Methanol decomposition on a clean polycrystalline copper oxide surface was studied by x-ray photoelectron spectroscopy (XPS). Methanol was adsorbed at 133 K and desorbed over a broad temperature range. When CuO was exposed to a very low dose of methanol vapor, dissociative adsorption takes place, leading to the formation of CH3O and H2O. This is attributed to the presence of preadsorbed oxygen on the CuO surface.

scholarly journals Rhodium Oxide Surface-Loaded Gas Sensors

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 892 ◽  
Author(s):  
Anna Staerz ◽  
Inci Boehme ◽  
David Degler ◽  
Mounib Bahri ◽  
Dmitry Doronkin ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Noble Metal ◽  
Noble Metals ◽  
Metal Cluster ◽  
Empirical Work ◽  
Oxide Surface ◽  
Metallic State ◽  
X Ray ◽  
Rhodium Clusters ◽  
Sensing Characteristics

In order to increase their stability and tune-sensing characteristics, metal oxides are often surface-loaded with noble metals. Although a great deal of empirical work shows that surface-loading with noble metals drastically changes sensing characteristics, little information exists on the mechanism. Here, a systematic study of sensors based on rhodium-loaded WO3, SnO2, and In2O3—examined using X-ray diffraction, high-resolution scanning transmission electron microscopy, direct current (DC) resistance measurements, operando diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and operando X-ray absorption spectroscopy—is presented. Under normal sensing conditions, the rhodium clusters were oxidized. Significant evidence is provided that, in this case, the sensing is dominated by a Fermi-level pinning mechanism, i.e., the reaction with the target gas takes place on the noble-metal cluster, changing its oxidation state. As a result, the heterojunction between the oxidized rhodium clusters and the base metal oxide was altered and a change in the resistance was detected. Through measurements done in low-oxygen background, it was possible to induce a mechanism switch by reducing the clusters to their metallic state. At this point, there was a significant drop in the overall resistance, and the reaction between the target gas and the base material was again visible. For decades, noble metal loading was used to change the characteristics of metal-oxide-based sensors. The study presented here is an attempt to clarify the mechanism responsible for the change. Generalities are shown between the sensing mechanisms of different supporting materials loaded with rhodium, and sample-specific aspects that must be considered are identified.

scholarly journals Acid-basic properties of chromium(III) oxide surface

2021 ◽  
Vol 57 (3) ◽  
pp. 270-277
Author(s):  
E. A. Shaporova ◽  
A. A. Zhukova ◽  
A. K. Baev ◽  
A. Yu. Sidorenko
Keyword(s):  
Binary Systems ◽  
Ionization Constant ◽  
Nitrate Solution ◽  
Structural Features ◽  
Oxide Surface ◽  
Acid Base ◽  
X Ray ◽  
Oxide Hydroxide ◽  
Nanosized Catalysts ◽  
Aqueous Nitrate Solution

The article is devoted to the study of the nature and number of acid-base centers on the surface of chromium(III) oxide obtained by precipitation from an aqueous nitrate solution. The curve of the distribution of the number of acidbase centers of the samples is plotted depending on the indicator of the ionization constant of indicators. It was determined that the main Lewis centers make the main contribution to the acidity of the samples; there are also Bronsted centers of different acidity. A comparative analysis of the structural features of the surface of oxides of chromium, zinc and binary systems Cr (III)–Zn (II) was carried out according to the results of X-ray phase analysis of oxides and thermolysis of the corresponding hydroxides. Based on this, the possibility of obtaining nanosized catalysts based on oxide-hydroxide systems of chromium with a number of 3d-metals obtained in the process of polynuclear hydroxocomplexation is predicted.

scholarly journals Surface film X-ray microanalysis

Scanning ◽  
1990 ◽  
Vol 12 (4) ◽  
pp. 212-224 ◽  
Author(s):  
J. L. Pouchou ◽  
F. Pichoir
Keyword(s):  
Surface Film ◽  
X Ray

Oxidation Behavior of Cu60Zr30Ti10 Bulk Metallic Glass

2005 ◽  
Vol 20 (6) ◽  
pp. 1396-1403 ◽  
Author(s):  
C.Y. Tam ◽  
C.H. Shek
Keyword(s):  
Metallic Glass ◽  
Oxide Layer ◽  
Bulk Metallic Glass ◽  
Photoelectron Spectroscopy ◽  
Oxidation Kinetics ◽  
Oxide Surface ◽  
X Ray ◽  
Rate Law ◽  
Cu Content ◽  
Surface Morphologies

The oxidation kinetics of Cu60Zr30Ti10 bulk metallic glass and its crystalline counterpart were studied in oxygen environment over the temperature range of 573–773 K. The oxidation kinetics, measured with thermogravimetric analysis, of the metallic glass follows a linear rate law between 573 and 653 K and a parabolic rate law between 673 and 733 K. It was also found that the oxidation activation energy of metallic glass is lower than that of its crystalline counterpart. The x-ray diffraction pattern showed that the oxide layer is composed of Cu2O, CuO, ZrO2, and metallic Cu. Cu enrichment on the topmost oxide layer of the metallic glass oxidized at 573 K was revealed by x-ray photoelectron spectroscopy while there was a decrease in Cu content in the innermost oxide layer. The oxide surface morphologies observed from scanning electron microscopy showed that ZrO2 granules formed at low temperatures while whiskerlike copper oxides formed at higher temperatures.

scholarly journals Structural Characterization of Graphene Oxide: Surface Functional Groups and Fractionated Oxidative Debris

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1180 ◽  
Author(s):  
Elvin Aliyev ◽  
Volkan Filiz ◽  
Muntazim M. Khan ◽  
Young Joo Lee ◽  
Clarissa Abetz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Functional Groups ◽  
Structural Model ◽  
Oxide Surface ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Surface Functional Groups ◽  
X Ray ◽  
Transmission Electron

The purpose of this work is the structural analysis of graphene oxide (GO) and by means of a new structural model to answer the questions arising from the Lerf–Klinowski and the Lee structural models. Surface functional groups of GO layers and the oxidative debris (OD) stacked on them were investigated after OD was extracted. Analysis was performed successfully using Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), X-ray photoemission spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, solid-state nuclear magnetic resonance spectroscopy (SSNMR), standardized Boehm potentiometric titration analysis, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The analysis showed that graphene oxide layers, as well as oxidative debris contain different functional groups such as phenolic –OH, ketone, lactone, carboxyl, quinone and epoxy. Based on these results, a new structural model for GO layers is proposed, which covers all spectroscopic data and explains the presence of the other oxygen functionalities besides carboxyl, phenolic –OH and epoxy groups.

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