scholarly journals Nitrided Silicon-Carbon Coatings Structure and Properties

2020 ◽  
Vol 98 (2) ◽  
pp. 7-17
Author(s):  
A.S. Rudenkov ◽  
◽  
A.V. Rogachev ◽  
S.M. Zavadski ◽  
D.A. Golosov ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Photoelectron Spectroscopy ◽  
Fold Increase ◽  
Graphite Phase ◽  
Carbon Coatings ◽  
Silicon Carbon ◽  
In Doping ◽  
Nitrogen Desorption ◽  
Nitrogen Ions ◽  
Thermal Stability Of

The paper considers structural and physicomechanical properties of silicon-carbon coatings deposited from a gaseous medium in doping with nitrogen ions. The analysis of the coatings by X-ray photoelectron spectroscopy shows that nitriding of silicon-carbon coatings promotes the formation of silicon nitride and compounds such as CNx and SixOyNz. A 1.5–2-fold increase in the content of sp2 -hybridized carbon and silicon carbide atoms is found to prevent silicon oxidation. Thermal annealing of the resulting silicon-carbon coatings increases the content of the graphite phase and silicon oxide.It is shown that doping of the working gas with nitrogen (Ar57 % + N43 %) leads to the formation of a more finely dispersed structure as compared to that when using argon only. During thermal annealing in air, the decreased carbon concentration and increased oxygen concentration can be observed due to silicon and carbon oxidation followed by desorption of carbon and oxygen compounds. In addition, annealing leads to nitrogen desorption from the coating. Nitriding of silicon-carbon coatings increases the dispersion of their structure, and heat-resistant compounds CNх, Si3N4 improve heat resistance and thermal stability of coatings, and increase microhardness and friction coefficient in friction units.

scholarly journals Improvement of the thermal stability of dendritic silver-coated copper microparticles by surface modification based on molecular self-assembly

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Tae Hyeong Kim ◽  
Hyeji Kim ◽  
Hyo Jun Jang ◽  
Nara Lee ◽  
Kwang Hyun Nam ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Electrically Conductive ◽  
X Ray ◽  
Alkyl Chains ◽  
Conductive Film ◽  
Initial Resistance ◽  
Thermal Stability Of ◽  
Scanning Electron

AbstractIn the study reported herein, silver-coated copper (Ag/Cu) powder was modified with alkanethiols featuring alkyl chains of different lengths, namely butyl, octyl, and dodecyl, to improve its thermal stability. The modification of the Ag/Cu powders with adsorbed alkanethiols was confirmed by scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Each powder was combined with an epoxy resin to prepare an electrically conductive film. The results confirmed that the thermal stability of the films containing alkanethiol-modified Ag/Cu powders is superior to that of the film containing untreated Ag/Cu powder. The longer the alkyl group in the alkanethiol-modified Ag/Cu powder, the higher the initial resistance of the corresponding electrically conductive film and the lower the increase in resistance induced by heat treatment.

Incorporation and Role of Nitrogen During Oxynitridation of Silicon Studied by Photoelectron Spectroscopy

1999 ◽  
Vol 567 ◽  
Author(s):  
Masayuki Suzuki ◽  
Yoji Saito
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Oxide Films ◽  
Silicon Surfaces ◽  
Gaseous Mixtures ◽  
X Ray ◽  
Initial Stage ◽  
Thermal Stability Of

ABSTRACTWe tried direct oxynitridation of silicon surfaces by remote-plasma-exited nitrogen and oxygen gaseous mixtures at 700°C in a high vacuum. The oxynitrided surfaces were investigated with in-situ X-ray photoelectron spectroscopy. With increase of the oxynitridation time, the surface density of nitrogen gradually increases, but that of oxygen shows nearly saturation behavior after the rapid increase in the initial stage. We also annealed the grown oxynitride and oxide films to investigate the role of the contained nitrogen. The desorption rate of oxygen from the oxynitride films is much less than that from oxide films. We confirmed that nitrogen stabilizes the thermal stability of these oxynitride films.

scholarly journals Phosphated Avocado Seed: A Renewable Biomaterial for Preparing a Flame Retardant Biofiller

2021 ◽  
Author(s):  
DAVID Zuluaga-Parra ◽  
L.F Ramos-deValle ◽  
Saul Sanchez ◽  
J.R. Torres-Lubián ◽  
J.A. Rodríguez-Gonzalez ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Chemical Modification ◽  
Flame Retardant ◽  
Photoelectron Spectroscopy ◽  
Morphological Changes ◽  
Ethylene Vinyl Acetate ◽  
Chemically Modified ◽  
Air Atmosphere ◽  
Thermal Stability Of ◽  
Avocado Seed

Abstract The cellulose and starch present in the avocado seed can be chemically modified to obtain biofillers with fire retarding characteristics. The resulting composites could be used as substitute of the corresponding halogenated composites. For this, the avocado seed was first washed, dehydrated and pulverized, and thereafter, chemically modified with phosphoric acid in the presence of urea. This was studied using infrared spectroscopy, nuclear magnetic resonance and X-Ray photoelectron spectroscopy, in order to determine the resulting chemical structure and confirm the presence of the proposed functional groups. In addition, scanning electron microscopy and elemental analysis were used, respectively, to establish the resulting morphological changes, as well as the elements present on the surface of the modified material. Thermogravimetric analysis was also carried out in order to establish the thermal stability of the material and predict the effect on the flame retardancy due to the mentioned chemical modification. Further tests established that the obtained modified structure and morphology of the avocado seed was highly dependent on the method used to dehydrate the pulverized avocado seed. It was also determined that chemical modification greatly increased the thermal stability of the avocado seed in air atmosphere. The flame-retardant effect of the modified avocado seed was assessed in polyethylene/ethylene-vinyl-acetate (PE/EVA) composites via cone calorimeter tests. These results showed that the modified avocado seed decreased the peak of the heat release rate (pHRR) by 50% and the total heat released (THR) by 15%. This phosphated avocado seed could be a good option as a renewable biofiller for polymer composites with enhanced flame-retardant properties.

scholarly journals Thermal Stability of Octadecyltrichlorosilane and Perfluorooctyltriethoxysilane Monolayers on SiO2

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 210
Author(s):  
Xiangdong Yang ◽  
Haitao Wang ◽  
Peng Wang ◽  
Xuxin Yang ◽  
Hongying Mao
Keyword(s):  
Thermal Stability ◽  
Thermal Behavior ◽  
Work Function ◽  
Photoelectron Spectroscopy ◽  
Vacuum Annealing ◽  
Moderate Temperature ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
X Ray ◽  
Thermal Stability Of

Using in situ ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) measurements, the thermal behavior of octadecyltrichlorosilane (OTS) and 1H, 1H, 2H, and 2H-perfluorooctyltriethoxysilane (PTES) monolayers on SiO2 substrates has been investigated. OTS is thermally stable up to 573 K with vacuum annealing, whereas PTES starts decomposing at a moderate temperature between 373 K and 423 K. Vacuum annealing results in the decomposition of CF3 and CF2 species rather than desorption of the entire PTES molecule. In addition, our UPS results reveal that the work function (WF)of OTS remains the same after annealing; however WF of PTES decreases from ~5.62 eV to ~5.16 eV after annealing at 573 K.

Characterizations of Ultra-thin Dielectrics Grown by Microwave Afterglow O2/N2O Plasma Oxidation at Low Temperature with Rapid Thermal Annealing

1995 ◽  
Vol 387 ◽  
Author(s):  
Po-ching Chen ◽  
Klaus Yung-jane Hsu ◽  
Joseph J. Loferski ◽  
Huey-liang Hwang
Keyword(s):  
Low Temperature ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Photoelectron Spectroscopy ◽  
Interface State ◽  
State Density ◽  
Interface State Density ◽  
Plasma Oxidation ◽  
X Ray ◽  
Thin Dielectrics

AbstractMicrowave afterglow plasma oxidation at a low temperature (600 °C ) and rapid thermal annealing (RTA) were combined to grow high quality ultra-thin dielectrics. This new approach has a low thermal budget. The mid-gap interface state density of oxides pretreated in N2O plasma was decreased to about 5×1010 cm−2eV−1 after rapid thermal annealing at 950 °C.It was found that RTA is very effective for relieving the oxide stress and reducing the interface state density. Nitrogen incorporated in oxides by the N2O plasma pretreatment of the Si surface helped to reduce the interface state density. Microstructures of ultra-thin oxide grown by microwave afterglow oxidation with or without RTA were revealed by extended-X-ray-absorption-finestructure (EXAFS) and X-ray photoelectron spectroscopy (XPS) analysis.

scholarly journals “PdO vs. PtO”—The Influence of PGM Oxide Promotion of Co3O4 Spinel on Direct NO Decomposition Activity

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 62 ◽  
Author(s):  
Gunugunuri K. Reddy ◽  
Torin C. Peck ◽  
Charles A. Roberts
Keyword(s):  
Photoelectron Spectroscopy ◽  
No Decomposition ◽  
Single Element ◽  
X Ray Diffraction ◽  
X Ray ◽  
Promotional Effect ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Thermal Stability Of

Direct decomposition of NO into N2 and O2 (2NO→N2 + O2) is recognized as the “ideal” reaction for NOx removal because it needs no reductant. It was reported that the spinel Co3O4 is one of the most active single-element oxide catalysts for NO decomposition at higher reaction temperatures, however, activity remains low below 650 °C. The present study aims to investigate new promoters for Co3O4, specifically PdO vs. PtO. Interestingly, the PdO promoter effect on Co3O4 was much greater than the PtO effect, yielding a 4 times higher activity for direct NO decomposition at 650 °C. Also, Co3O4 catalysts with the PdO promoter exhibit higher selectivity to N2 compared to PtO/Co3O4 catalysts. Several characterization measurements, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR), and in situ FT-IR, were performed to understand the effect of PdO vs. PtO on the properties of Co3O4. Structural and surface analysis measurements show that impregnation of PdO on Co3O4 leads to a greater ease of reduction of the catalysts and an increased thermal stability of surface adsorbed NOx species, which contribute to promotion of direct NO decomposition activity. In contrast, rather than remaining solely as a surface species, PtO enters the Co3O4 structure, and it promotes neither redox properties nor NO adsorption properties of Co3O4, resulting in a diminished promotional effect compared to PdO.

The Phase Composition and Structure of Silicon-Carbon Coatings

2019 ◽  
Vol 970 ◽  
pp. 283-289
Author(s):  
Alexander S. Rudenkov ◽  
Alexander V. Rogachev ◽  
Alexander N. Kupo ◽  
Petr A. Luchnikov ◽  
Nataliya Chicherina
Keyword(s):  
Heat Treatment ◽  
Silicon Carbide ◽  
Phase Composition ◽  
Ion Beam ◽  
Ion Source ◽  
Ion Beam Sputtering ◽  
Carbon Coatings ◽  
Silicon Carbon ◽  
Composition And Structure ◽  
Beam Sputtering

The effect of the formation and heat treatment modes of silicon-carbon coatings deposited by ion-beam sputtering of silicon carbide on their morphology, chemical and phase composition is determined. It has been established that an increase in the power of the ion source from 432 W to 738 W leads to a decrease in the sp3/sp2 phase ratio by 1.7 times and an increase in the ratio of Si-C/Si-O bonds by 1.9 times. It is shown that doping of carbon coatings with silicon carbide increases their heat resistance.

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