Influence Of Oxygen Flow Rate Research Articles

An Influence of Oxygen Flow Rate and Spray Distance on the Porosity of HVOF Coating and Its Effects on Corrosion—A Review

Thermal spray coating, exceptionally high-velocity oxyfuel (HVOF), improves the corrosion resistance and wear of metal. Coating parameters play a vital role in the properties of the coating. The quality of coating can be increased by selecting appropriate coating parameters. In the case of HVOF, the oxygen flow rate and spray distance are the most significant parameters that directly influence the porosity and corrosion resistance of the coating. Porosity is essential in thermal barrier coatings for low thermal conductivity, but there is a limit of porosity beyond which it can cause failure. Hence, understanding the effects of these parameters is essential to evaluate and further minimize the porosity in order to improve the corrosion resistance and durability of the thermal barrier coating. This article reviews hot corrosion in thermal barrier coatings, the stages of corrosion, the importance of spray parameters, and the effect of the oxygen flow rate and spray distance on the corrosion resistance of HVOF-sprayed coatings. Afterwards, the coating materials, the substrate, the flow rate of oxygen, the spray distance, and the fuel used during the HVOF spraying process from recent articles are summarized. In summary, this review compares the flow rate of oxygen and the spray distance with the corrosion capacity of the coating under different corrosive environments and materials to optimize these parameters for high-quality coating, which would sustain under high temperatures for future applications.

Influence of oxygen flow rate and annealing temperature on composition, microstructure and mechanical properties of Fe–O films by reactive magnetron sputtering

Using reactive magnetron sputtering, Fe–O films were prepared independently under different oxygen flow rates. The transitions of composition and structure by changing the oxygen flow rate and annealing treatment were studied. Single Fe3O4 was only maintained at a low Ar/O2 flux ratio of 20:0.2, and then α-Fe2O3 could appear and completely replace Fe3O4 when the Ar/O2 flux ratio reached 20:1. By annealing, the Fe3O4 film can transform into FeO, while the α-Fe2O3 film has excellent thermal stability. The growth mode, surface morphology and roughness of the deposited and annealed Fe–O films were investigated by scanning electron microscope (SEM) and optical profiler. The nanoindentation technique was used to measure the hardness and elastic modulus of the Fe–O films prepared at different oxygen flow rates and annealed at different temperatures. From the viewpoint of structure doping and release of compressive residual stress, the change tendency of nano-mechanical properties was discussed in detail.

Influence of Oxygen Flow Rate on the Properties of FeOXNY Films Obtained by Magnetron Sputtering at High Nitrogen Pressure

Fe-O-N films were successfully deposited by magnetron sputtering of an iron target in Ar-N2-O2 reactive mixtures at high nitrogen partial pressure 1.11 Pa (Q(N2) = 8 sccm) using a constant flow rate of argon and an oxygen flow rate Q(O2) varying from 0 to 1.6 sccm. The chemical composition and the structural and microstructural nature of these films were characterized using Rutherford Backscattering Spectrometry, X-ray diffraction, and Conversion Electron Mössbauer Spectrometry, respectively. The results showed that the films deposited without oxygen are composed of a single phase of γ″-FeN, whereas the other films do not consist of pure oxides but oxidelike oxynitrides. With higher oxygen content, the films are well-crystallized in the α-Fe2O3 structure. At intermediate oxygen flow rate, the films are rather poorly crystallized and can be described as a mixture of oxide γ-Fe2O3/Fe3O4. In addition, the electrical behavior of the films evolved from a metallic one to a semiconductor one, which is in total agreement with other investigations. Comparatively to a previous study carried out at low nitrogen partial pressure (0.25 Pa), this behavior of films prepared at higher nitrogen partial pressure (1.11 Pa) could be caused by a catalytic effect of nitrogen on the crystallization of the hematite structure.

An Influence of Oxygen Flow Rate on Structural, Optical and Tribological Properties of Molybdenum Oxide Thin Films

The influence of oxygen flow rate is examined on structural, optical and tribological properties of molybdenum oxide films deposited by reactive magnetron sputtering. The films were characterized by X-ray diffraction, scanning electron microscope (SEM), and contact angle measurement system. The optical properties of the films were measured by UV-Vis-NIR spectrophotometer and transmittance of ∼73% in the visible region of the spectrum was achieved. The band gap increases with increases in oxygen gas flow rate. AFM figure illustrates that the roughness of surface increases as oxygen flow rate increases. As oxygen increases wear rate and COF decreases while at the 18 sccm the lowest wear rate found.

Temperature dependent elastic modulus of HVOF sprayed Ni-5%Al on 304 stainless steel using nondestructive laser ultrasound technique

In this study, NiAl coating was produced on 304 stainless steel material using High velocity oxygen-fuel (HVOF) spray technique. The influence of oxygen flowrate on the microstructure, porosity and hardness of the coating was investigated. Further, the mechanical properties of HVOF sprayed samples were determined at various temperatures using optical, laser excitation with interferometer reception, completely non-contact and nondestructive based laser ultrasound technique. The outcomes of this study indicate that the microstructure and properties of the coatings are sensitive to the oxygen flowrate. A coating with highest hardness and less porosity was achieved while increasing the oxygen content. Higher Young's modulus was observed at 20 °C and gradually decreases with the rise in temperature. The behavior of Young's modulus and Poisson's ratio at elevated temperature indicates that originate from the existence of a gas flow rate in the NiAl coating, leading to reduced flexural strength with increased temperature. Both inversion and experimentation result shows a good agreement in elastic properties of HVOF coated sample. The proposed laser ultrasound technique is valid for remote, noncontact and nondestructive characterization of the Young's modulus and Poisson's ratio of the coatings in elevated temperature environments.

Processing, structure and properties of reactively sputtered films of titanium dioxide and suboxides

A series of TiOx(0 < x ≤ 2) thin films with different O/Ti ratio were deposited on Si substrates by reactive magnetron sputtering of Ti metal in Ar + O2 plasma. The influence of oxygen flow rate and substrate temperature on the structural, mechanical, and electrical properties of the films was explored. With increasing the oxygen flow rate, the following phases appeared in the following order: Ti metal, Ti(O) solid solution, TiO, Ti2O3, Magnéli phases, rutile and anatase TiO2. With increasing the temperature, the crystallinity, and oxygen content of the films varied, which resulted in changes in film properties. The trend of hardness and electrical conductivity in ceramic TiOx films is TiO > Ti2O3 > Magneli phases > rutile phase.

Influence of oxygen flow rate and substrate positions on properties of Cu-oxide thin films fabricated by radio frequency magnetron sputtering using pure Cu target

Cu oxide thin films have been deposited by radio frequency magnetron sputtering in an ambient of argon and oxygen using a pure Cu target. The structural, electrical and optical properties were investigated systematically as a function of O2 flow rate and substrate positions, revealing that the O2 flow rate and substrate positions have a strong influence on both composition and functional properties of the resulting Cu oxide films. Particularly, the films tend to change towards Cu2O, Cu4O3 and CuO single and bi-phase with increasing the O2 flow rate. Optical absorption properties were analyzed for the single phase Cu2O, Cu4O3, and CuO films prepared in this study, demonstrating the potential of Cu4O3 and CuO as an absorber material for the photovoltaic application.

Influence of oxygen flow rate on structural, optical and electrical properties of copper oxide thin films prepared by reactive magnetron sputtering

In this research, copper oxide thin films were prepared by reactive dc magnetron sputtering method on glass substrates with oxygen flow rate in the range of 1-10 sccm. From XRD patterns, formation of Cu2O cubic structure or CuO monoclinic structure was controlled by adjusting oxygen flow rate. Nanocrystallite size of the as-grown films was observed by AFM. From transmittance spectra, direct energy gap varied between 1.97 and 2.55 eV. Electrical conductivity and Hall effect measurements were performed on the films with van der Pauw configuration. The positive sign of the Hall coefficient confirmed the p-type conductivity in all studied films. Important electrical parameters of films as a function of oxygen flow rate were observed. With low resistivity and high mobility values, the films prepared at oxygen flow rate of 8 sccm are identified as suitable candidates for fabrication as absorber layer in solar cell devices.

Influence of oxygen flow rate on metal–insulator transition of vanadium oxide thin films grown by RF magnetron sputtering

High-quality vanadium oxide (VO2) films have been fabricated on Si (111) substrates by radio frequency (RF) magnetron sputtering deposition method. The sheet resistance of VO2 has a significant change (close to 5 orders of magnitude) in the process of the metal–insulator phase transition (MIT). The field emission-scanning electron microscope (FE-SEM) results show the grain size of VO2 thin films is larger with the increase of oxygen flow. The X-ray diffraction (XRD) results indicate the thin films fabricated at different oxygen flow rates grow along the (011) crystalline orientation. As the oxygen flow rate increases from 3 sccm to 6 sccm, the phase transition temperature of the films reduces from 341 to 320 K, the width of the thermal hysteresis loop decreases from 32 to 9 K. The thin films fabricated in the condition of 5 sccm have a high temperature coefficient of resistance (TCR) −3.455%/K with a small resistivity of 2.795 ρ/Ω cm.

Influence of oxygen flow rate on electrochromic property of WO3 nanorods prepared by glancing reactive magnetron sputtering

Tungsten oxide (WO3) is widely applied as an electrochromic layer for several smart window applications. The objective of this research is to develop the nanostructure of WO3 films with high electrochromic response. The one dimensional nanostructure of WO3 films was prepared by glancing-angle deposition (GLAD) technique; the tungsten oxide nanorods (WO3 NRs) were deposited onto indium tin oxide substrate by DC reactive magnetron sputtering. The effect of oxygen flow rate on the properties of WO3 NRs films was investigated by varying the oxygen flow rate from 12 - 30 sccm, during the deposition of the films. Then, the electrochromic property, the coloring-bleaching and the morphological of the films were characterized by cyclic voltammetry (CV), spectrophotometry and field-emission scanning electron microscopy (FESEM), respectively. We study the effect of ion insertion into the WO3 NRs by varying the doping ions - H+, Na+ and Li+ - and measuring the property by CV. The results showed that the insertion of H+ into the WO3 NRs films is faster than that of the others. Moreover, the CV peak and the film transmittance different between coloring and bleaching periods indicated that the electrochromic response increased as the oxygen flow rates were increased. In addition, the nanorods of the WO3 films were confirmed by FESEM. The influence of oxygen flow rate on morphology and electrochromic property has been discussed.

Influence of oxygen flow rate on the structural, optical and electrical properties of ZnO films grown by DC magnetron sputtering

Zinc oxide thin films were deposited on glass substrates at different oxygen flow rates by DC reactive magnetron sputtering. The oxygen flow rate was found to be one of the crucial parameters which influence structural, optical and electrical properties of grown films. The structural and optical characterization of the deposited films was carried out using X-ray diffraction and UV–visible spectroscopy, respectively. Swanepoel envelope and Drude–Lorentz (DL) models were applied to extract the optoelectronic parameters such as refractive index, dispersion energy and plasma frequency. Structurally, grain size was found to decrease with increase in oxygen flow rate during deposition. Moreover, all the films exhibited preferred (002) orientation confirming c-axis orientation of the films perpendicular to the substrate. For a particular range of oxygen flow rates, columnar growth was achieved. Marginal increase in the optical band gap from 3.14 to 3.22 eV was observed as the oxygen flow rate increased from 3 to 10 sccm. Calculated plasma frequency from the DL model was found to be in the infrared region. It has decreased as oxygen flow rate increased with the value from 1.625 × 1014 rad/s (862 cm−1) to 1.072 × 1014 rad/s (568 cm−1).

Influence of Oxygen Flow Rate on the Characteristics of the Tungsten Oxide Using RF Magnetron Sputtering

—Tungsten Oxide (WO3) thin films were deposited using 99.9% pure tungsten target onto ITO substrate using RF magnetron sputtering in the range oxygen flow rates of 30-50%. The influence of the oxygen flow rate on characteristic of WO3 thin films has been investigated. The transmittance, resistivity, crystallite, roughness, and surface morphology were measured by UV-Vis, 2-point probe, X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), and Field Emission Scanning Electron Microscopy (FE-SEM) respectively. Experimental result showed that the deposition rate of WO3 thin films decreased by increasing oxygen flow rate. A poor crystalinity or more too amorphous of WO3 thin films produces by using various oxygen content. A higher optical transmittance spectrum detected at 30% oxygen content about 86% at wavelength 550nm. Keywords—TungstenOxide(WO3);RFsputtering,sputteringoxygen

Influence of Oxygen Flow Rate on Sputter Deposition Rate and SEM Image of Copper Oxide Thin Films

Recently, copper oxide thin film has been studied because of its low cost, sensitivity to ambient condition and easiness to produce oxide thin film. It is one of the p-type semiconductor oxides materials that are suitable to be used as gas sensing material. In order to improve the sensitivity and to optimize the properties of copper oxide thin film, it is essential to study the physical structure of copper oxide. In current studies, copper oxide thin film has been deposited by RF magnetron sputtering at different substrate bias voltages and oxygen flow rates. The results reveal that the deposition rate decreased when the oxygen flow rate above 4 sccm. SEM image reveal that nanostructure copper oxide was also obtained when the oxygen flow rate was above 4 sccm. On the other hand, no significant effect on the substrate bias voltage toward the sputter deposition rate was observed.

The influence of oxygen flow rate on properties of SnO2 thin films grown epitaxially on c-sapphire by chemical vapor deposition

Tin dioxide (SnO2) thin films were grown on c-plane sapphire substrates by chemical vapor deposition using SnI2 and O2 as reactants. The growth experiments were carried out at a fixed substrate temperature of 510°C and different O2 flow rates. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, UV–Vis–IR spectrophotometry and Hall-effect measurement were used to characterize the films. All films consisted of pure-phase SnO2 with a rutile structure and showed an epitaxial relationship with the substrate of SnO2(100)||Al2O3(0001) and SnO2[010]||Al2O3<11–20>. The crystalline quality and properties of the films were found to be sensitively dependent on the O2 flow rate during the film growth. The absolute average transmittance of the SnO2 films exceeded 85% in the visible and infrared spectral region. The films had optical band-gaps (3.72–3.89eV) that are in line with the band gap of single-crystal SnO2. The carrier concentration and Hall mobility of the films decreased from 3.3×1019 to 9×1017cm−3 and from 19 to 2cm2V−1s−1, respectively, while the resistivity increased from 0.01 to 3Ωcm with increasing of the O2 flow rate from 5 to 60sccm.

Tuning the structure and preferred orientation in reactively sputtered copper oxide thin films

Binary copper oxide (Cu2O, Cu4O3 and CuO) thin films have been selectively deposited on glass and silicon substrates by magnetron sputtering at room temperature from a metallic copper target in various Ar–O2 reactive mixtures. The influence of oxygen flow rate and total pressure on the film structure and its preferred orientation has been studied. A schematic deposition diagram, which describes the film structure as a function of O2 flow rate and total pressure, is depicted by combining X-ray diffraction and Raman spectrometry. The oxygen flow rate process windows for Cu2O or Cu4O3 single phase synthesis are narrow, while that for CuO is wider. Between two single phase domains, biphase films are systematically deposited. It is found that the deposition total pressure is a relevant parameter to control the texture and the morphology of pure Cu2O and Cu4O3 films. Low total pressure favors the growth of planes with high surface energy ((100) for Cu2O and (101) for Cu4O3) parallel to the substrate. On the other hand, high total pressure facilitates the growth of planes with low surface energy ((111) for Cu2O and (100) for Cu4O3). The oxygen flow rate is effective to control the preferred orientation of CuO thin films that evolves from 〈111〉 to 1¯ 1 1 with the increase of oxygen flow rate. These results are supported by transmission electron microscopy observation in cross section.

Characterization of fluorinated silica thin films with ultra-low refractive index deposited at low temperature

Structural and optical properties of low refractive index fluorinated silica (SiOxCyFz) films were investigated. The films were deposited on p-type silicon and polycarbonate substrates by radio frequency plasma enhanced chemical vapor deposition method at low temperatures. A mixture of tetraethoxysilane vapor, oxygen, and CF4 was used for deposition of the films. The influence of oxygen flow rate on the elemental compositions, chemical bonding states and surface roughness of the films was studied using energy dispersive X-ray analyzer, Fourier transform infrared spectroscopy in reflectance mode and atomic force microscopy, respectively. Effects of chemical bonds of the film matrix on optical properties and chemical stability were discussed. Energy dispersive spectroscopy showed high fluorine content in the SiOxCyFz film matrix which is in the range of 7.6–11.3%. It was concluded that in fluorine content lower than a certain limit, chemical stability of the film enhances, while higher contents of fluorine heighten moisture absorption followed by increasing refractive index. All of the deposited films were highly transparent. Finally, it was found that the refractive index of the SiOxCyFz film was continuously decreased with the increase of the O2 flow rate down to the minimum value of 1.16±0.01 (at 632.8nm) having the most ordered and nano-void structure and the least organic impurities. This sample also had the most chemical stability against moisture absorption.

Influence of oxygen flow rate in CuO

The structural, optical and electrical properties of cupric oxide (CuO) films coated by DC magnetron sputtering method under different oxygen flow rate (0%, 35%, 70%) were examined. The electrical transport mechanism of the films was also investigated in a temperature range of 110–400K. Electrical conductivity of the films mainly affected by oxygen flow rate since density of states (DOS) was critically dependent on the oxygen flow rate. Considering oxygen flow rate, a direct link between the DOS and electrical properties of the films was established.

Influence of oxygen flow rate on the surface chemistry and morphology of radio frequency (RF) magnetron sputtered zinc oxide thin films

Zinc oxide thin films were deposited, by radio frequency magnetron sputtering, on heated and unheated substrates. The oxygen flow rate was varied during deposition, and its effects on the structural and chemical properties of the films were investigated. The films had oriented c‐axis growth with nano‐crystallite size. Their surfaces manifested columnar microstructure, with a surface roughness that was suppressed by the introduction of oxygen. Chemical analysis showed that deposition under an oxygen atmosphere resulted in substantial reduction of oxygen vacancies, with a corresponding incorporation of chemisorbed species. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Influence of oxygen flow rate and compost addition on reduction of organic matter in aerated waste layer containing mainly incineration residue

Landfilling municipal solid waste incineration (MSWI) residue alkalizes the waste layer, causing a subsequent decrease in microbial activity and a delay in the decomposition of organic matter. In this study, efficiencies of neutralization of the leachate and organic matter decomposition in the waste layer in a column filled with MSWI residue using aeration and compost addition were evaluated. Total organic carbon (TOC) reduction in the waste layer is large at high oxygen flow rate (OFR). To effectively accelerate TOC reduction in the waste layer to which compost was added, a high OFR exceeding that by natural ventilation was required. At day 65, the pH of the leachate when OFR was above 102 mol-O2/(day·m3) was lower than that when OFR was below 101 mol-O2/(day·m3). At the same OFR, the pH of waste sample was lower than that of waste sample with compost. Although leachate neutralization could be affected by compost addition, TOC reduction in the waste layer became rather small. It is possible that humic substances in compost prevent the decomposition of TOC in MSWI residue.

The effect of oxygen flow rates on magnetic and high‐frequency characteristics of Fe‐Hf‐O films

AbstractThis study aimed to investigate the influence of oxygen flow rate on magnetic and high‐frequency properties of as‐deposited FeHfO thin films, which were fabricated by DC reactive magnetron sputtering in an Ar + O2 atmosphere. These films exhibited mixed phases of α‐Fe nanograins and amorphous HfO2 phase, showing nanocrystalline structure and soft magnetic properties. The dispersion character of FeHfO films changed from relaxation‐type to resonance‐type when the oxygen flow rate varied from 1.0 to 1.2 sccm. Furthermore, the Fe58.8Hf13.1O28.1 film with the optimum O2 flow rate of 1.2 sccm exhibited high saturation magnetization of 10.6 kG, a high resistivity of 258 µΩ cm, a real component of permeability (µ′) of 250 up to 1 GHz and a high ferromagnetic resonance frequency of 2.5 GHz. It is expected that this film should be promising for practical applications as a high‐frequency ferromagnetic material.