scholarly journals Oxidation Stabilization of ZrFe Alloys in Nitrogen Gas Atmosphere

2021 ◽  
Vol 59 (10) ◽  
pp. 754-760
Author(s):  
Kwangbae Kim ◽  
Saera Jin ◽  
Yesol Lim ◽  
Hyunjun Lee ◽  
Seonghoon Kim ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Elevated Temperatures ◽  
Nitrogen Atmosphere ◽  
Metallic Silver ◽  
X Ray Diffraction ◽  
Alloy Specimen ◽  
Surface Color ◽  
Nitrogen Gas ◽  
X Ray ◽  
Gas Atmosphere

A porous ZrFe alloy specimen was prepared as a 6 × 3 mm (diameter × thickness) disk. The reaction of the ZrFe alloy was confirmed while the whole system was maintained at a target temperature, which was increased from 150 oC to 950 oC in a 99.999% low purity nitrogen atmosphere, consisting of 10 ppm of impurity gas. Surface color, pore size, stabilized layer, and phase change were confirmed with optical microscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Micro-Raman, according to temperature. The surface color of the ZrFe alloy changed from metallic silver to dark gray as the temperature increased. In the EDS and XPS results, nitrogen component was not observed, and oxygen content increased on each surface at the elevated temperatures. In this way, the ZrFe alloy was stabilized in a low purity nitrogen atmosphere, preventing rapid nitride reactions.

scholarly journals Oxidation Stabilization of ZrFe Alloys in Nitrogen Gas Atmosphere

2021 ◽  
Vol 59 (10) ◽  
pp. 753-759
Author(s):  
Kwangbae Kim ◽  
Saera Jin ◽  
Yesol Lim ◽  
Hyunjun Lee ◽  
Seonghoon Kim ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Elevated Temperatures ◽  
Nitrogen Atmosphere ◽  
Metallic Silver ◽  
X Ray Diffraction ◽  
Alloy Specimen ◽  
Surface Color ◽  
Nitrogen Gas ◽  
X Ray ◽  
Gas Atmosphere

A porous ZrFe alloy specimen was prepared as a 6 × 3 mm (diameter × thickness) disk. The reaction of the ZrFe alloy was confirmed while the whole system was maintained at a target temperature, which was increased from 150 oC to 950 oC in a 99.999% low purity nitrogen atmosphere, consisting of 10 ppm of impurity gas. Surface color, pore size, stabilized layer, and phase change were confirmed with optical microscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Micro-Raman, according to temperature. The surface color of the ZrFe alloy changed from metallic silver to dark gray as the temperature increased. In the EDS and XPS results, nitrogen component was not observed, and oxygen content increased on each surface at the elevated temperatures. In this way, the ZrFe alloy was stabilized in a low purity nitrogen atmosphere, preventing rapid nitride reactions.

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.

Reduced electrical resistivity of reaction-sintered SiC by nitrogen doping

2008 ◽  
Vol 23 (4) ◽  
pp. 1020-1025 ◽  
Author(s):  
Young-Sam Jeon ◽  
Hyunho Shin ◽  
Young-Hyun Lee ◽  
Sang-Won Kang
Keyword(s):  
Heat Treatment ◽  
Electrical Resistivity ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Doping ◽  
Nitrogen Atmosphere ◽  
X Ray Diffraction ◽  
Post Heat Treatment ◽  
X Ray ◽  
Sic Particles ◽  
Transmission Electron

A post heat treatment of reaction-sintered SiC at 1700 °C in nitrogen atmosphere significantly reduced electrical resistivity. A trace of insulating Si3N4 phase was detected via nitrogen heat treatment in high-resolution transmission electron microscopy observation; however, based on x-ray photoelectron spectroscopy, the evidence of nitrogen doping into SiC lattice has been claimed as the mechanism to the decreased resistivity. The increase of the total volume of SiC was apparent in x-ray diffraction during the nitrogen heat treatment, which was interpreted to stem from the growth of the nitrogen-doped intergranular SiC particles and surface doping of the primary SiC to reduce the contact resistance between the primary SiC particles.

scholarly journals Acetaldehyde Adsorption Characteristics of Ag/ACF Composite Prepared by Liquid Phase Plasma Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2344
Author(s):  
Byung-Joo Kim ◽  
Kay-Hyeok An ◽  
Wang-Geun Shim ◽  
Young-Kwon Park ◽  
Jaegu Park ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Photoelectron Spectroscopy ◽  
Silver Oxide ◽  
Activated Carbon Fiber ◽  
Metallic Silver ◽  
X Ray Diffraction ◽  
Adsorption Experiment ◽  
X Ray ◽  
Ag Particles ◽  
Liquid Phase Plasma

Ag particles were precipitated on an activated carbon fiber (ACF) surface using a liquid phase plasma (LPP) method to prepare a Ag/ACF composite. The efficiency was examined by applying it as an adsorbent in the acetaldehyde adsorption experiment. Field-emission scanning electron microscopy and energy-dispersive X-ray spectrometry confirmed that Ag particles were distributed uniformly on an ACF surface. X-ray diffraction and X-ray photoelectron spectroscopy confirmed that metallic silver (Ag0) and silver oxide (Ag2O) precipitated simultaneously on the ACF surface. Although the precipitated Ag particles blocked the pores of the ACF, the specific surface area of the Ag/ACF composite material decreased, but the adsorption capacity of acetaldehyde was improved. The AA adsorption of ACF and Ag/ACF composites performed in this study was suitable for the Dose–Response model.

scholarly journals Design of Defect and Metallic Silver in Silver Phosphate Photocatalyst Using the Hydroxyapatite and Glucose

2020 ◽  
Vol 20 (6) ◽  
pp. 1441
Author(s):  
Uyi Sulaeman ◽  
Suhendar Suhendar ◽  
Hartiwi Diastuti ◽  
Roy Andreas ◽  
Shu Yin
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Glucose Solution ◽  
Reflectance Spectroscopy ◽  
Metallic Silver ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silver Phosphate ◽  
Agno3 Aqueous Solution

The defect and metallic silver (Ag) in silver phosphate (Ag3PO4) photocatalyst were successfully generated using hydroxyapatite (HA) and glucose. Two steps of synthesis were done in these experiments. Firstly, the Ag/HA powder was prepared by reacting AgNO3 and HA, followed by the addition of a glucose solution. Secondly, the suspension of Ag/HA was reacted with AgNO3 aqueous solution. The yellow product of Ag/Ag3PO4 photocatalyst was produced. The products were characterized using X-Ray Diffraction (XRD), Diffuse Reflectance Spectroscopy (DRS), Scanning Electron Microscope (SEM), Brunauer–Emmett–Teller (BET) and X-ray Photoelectron Spectroscopy (XPS). The decreased ratio of O/Ag and metallic Ag formation observed by the XPS was detected as the possible defect and Ag-doping in the photocatalyst. The enhanced photocatalytic activity might be caused by the oxygen vacancy and metallic Ag in Ag3PO4 that enables the separation of photo-generated electrons and holes.

scholarly journals Structure and photocatalytic properties of sintered TiO2 nanotube arrays

2018 ◽  
Vol 50 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Jelena Vujancevic ◽  
Andjelika Bjelajac ◽  
Jovana Cirkovic ◽  
Vera Pavlovic ◽  
Endre Horvath ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Tio2 Nanotubes ◽  
Elevated Temperatures ◽  
Uv Light ◽  
Tio2 Nanotube ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Tio2 ◽  
Nanotube Films

One-dimensional (1D) TiO2 nanotubes perpendicular to the substrate were obtained by electrochemical oxidation of titanium foil in an acid electrolyte. In order to alter the crystallinity and the morphology of films the as-anodized amorphous TiO2 nanotube films were sintered at elevated temperatures. The evolution of the morphology was visualized via scanning electron microscopy (SEM), while the crystalline structure was investigated by X-ray diffraction (XRD) and Raman spectroscopy. The chemical composition was studied by X-ray photoelectron spectroscopy (XPS). The effects of crystallinity and morphology of TiO2 nanotube (NTs) films on photocatalytic degradation of methyl orange (MO) in an aqueous solution under UV light irradiation were also investigated. The TiO2 nanotubes sintered at 650?C for 30 min had the highest degree of crystallinity and exhibited the best photocatalytic activity among the studied TiO2 nanotube films.

Effects of NaBH4 Additions on Hydrogen Absorption by Nanostructured FeTi Powders

2008 ◽  
Vol 587-588 ◽  
pp. 921-925 ◽  
Author(s):  
Sofia F. Marques ◽  
Raquel A. Silva ◽  
Jose Brito Correia ◽  
Nobumitsu Shohoji ◽  
Carmen M. Rangel
Keyword(s):  
Hydrogen Absorption ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Low Cost ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gas Atmosphere ◽  
Scanning Electron

FeTi intermetallic powders are very promising media for reversible hydrogen storage. However, difficult activation treatments including annealing at elevated temperatures in high pressure H2 gas atmosphere are mandatory. In the present work nanostructured FeTi powders were produced and activated in situ at room temperature using mechanical alloying/milling (MA/MM) of pure metallic constituents, Fe and Ti, added with sodium borohydride. The resultant powders, FeTiHx, already H2 pre-charged, absorbed a significant amount of H2 but require optimization for reversible absorption/desorption. This system has one of the highest volumetric storage capacities and can be produced at low cost. Several parameters of the as-milled powders were controlled. The phase constitution of the reaction products was characterized by X-ray diffraction and scanning electron microscopy and the absorption isotherms of the activated powders were determined.

Influences of oxygen impurity contained in nitrogen on the reaction of titanium with nitrogen

2009 ◽  
Vol 24 (7) ◽  
pp. 2400-2408 ◽  
Author(s):  
Fu-Hsing Lu ◽  
Bor-Feng Jiang ◽  
Jen-Li Lo ◽  
Mu-Hsuan Chan
Keyword(s):  
Low Temperatures ◽  
Nitrogen Atmosphere ◽  
Model System ◽  
Oxygen Impurity ◽  
X Ray Diffraction ◽  
Nitrogen Gas ◽  
X Ray ◽  
Partial Pressures

In this work, Ti pellets were selected as a model system to investigate the influences of oxygen impurity in nitrogen gas on the reaction of a metal with the nitrogen. Analyzing changes in the in situ oxygen partial pressures when titanium specimens were annealed in the oxygen-containing nitrogen shows that the dissolution of oxygen in Ti and TiNx is exothermic, and the solubility decreases as the temperature increases. X-ray diffraction results show that nitridation of Ti occurred before oxidation, even in an oxygen-containing nitrogen atmosphere. Kinetics apparently predominates over thermodynamics at low temperatures in such a system.

scholarly journals Synthesis of h-BN by the Combustion of B/KNO3/Octogen Mixture under Nitrogen Atmosphere

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Song-qi Hu ◽  
Yin Wang ◽  
Lin-lin Liu
Keyword(s):  
High Purity ◽  
Photoelectron Spectroscopy ◽  
Hexagonal Boron Nitride ◽  
Nitrogen Atmosphere ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistance To Oxidation ◽  
Scanning Electron ◽  
Main Impurity

Hexagonal boron nitride (h-BN) powders were fabricated by the combustion synthesis with B/KNO3/HMX (octogen) mixtures as reactants. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were adopted to investigate the phase composition and the chemical composition of the products, respectively. The morphology and resistance to oxidation were studied by scanning electron microscopy (SEM) and thermogravimetry (TGA), respectively. The characterization results showed that the h-BN which was produced through this method has high purity and exhibits excellent resistance to oxidation. The purity of h-BN is improved with the increasing content of HMX in reactants with boron carbide (B4C) and boron oxide (B2O3) as main impurity, but conversely, the yields are obviously decreased. Taking the comprehensive consideration of the purity and the yields together, the optimal molar ratio of B/KNO3/HMX is 10 : 1 : 4. In addition, the experimental results indicated that the crystalline grain size grows with the increasing content of HMX. The method explored in this study does not need expensive processing facilities and equipment, which is a preferable approach for the laboratory to prepare h-BN of high purity.

scholarly journals A Study on the Transition of Copper Oxide by the Incorporation of Nitrogen

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1099 ◽  
Author(s):  
Song-Yi Ahn ◽  
Kyung Park ◽  
Daehwan Choi ◽  
Jozeph Park ◽  
Yong Joo Kim ◽  
...  
Keyword(s):  
Copper Oxide ◽  
Photoelectron Spectroscopy ◽  
Gas Flow ◽  
Oxide Semiconductor ◽  
X Ray Diffraction ◽  
Nitrogen Gas ◽  
Flow Rates ◽  
X Ray ◽  
Nitrogen Incorporation ◽  
P Type

In the present study, the effects of nitrogen incorporation on the transition of a p-type copper oxide semiconductor are investigated. The properties of sputtered copper oxide and nitrogen-incorporated copper oxide are evaluated and compared at various nitrogen gas flow rates. The results indicate that the addition of nitrogen results in an increased optical bandgap, accompanied by significantly reduced tail states compared to pristine copper oxide. In addition, X-ray diffraction and X-ray photoelectron spectroscopy reveal that the incorporation of nitrogen stimulates the transition from copper (II) oxide to copper (I) oxide.

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