Oxide Composite Films Research Articles

Study on Parameter Correlation of Thickness and Performance of Anodizing Film on 6061 Aluminum Alloy Frame in High Energy Laser System

As stray laser light is difficult to avoid in high-energy laser systems, it is of great significance to improve the laser damage resistance of the aluminum alloy frame anodizing film system. In this paper, the effects of anodic oxidation parameters on the thickness and performance of 6061 aluminium alloy anodic oxide composite film systems are investigated combining experiments and simulations. The thickness of the oxide film is calculated theoretically, and the simulation model is established. Then the effects of anodizing parameters and the reasons are analyzed. After characterizing the surface quality and laser damage resistance of the oxide film, the influence of anodizing parameters is summarized. This paper enables advance calculations of film thickness within a certain range, combined with the film properties, to provide a reference for the laboratory preparation of 6061 anodizing films and the preparation of structure-specific composite film systems based on the film.

TiO2–Graphene Oxide and TiO2–Reduced Graphene Oxide Composite Thin Films for Solar Photocatalytic Wastewater Treatment

This research reports on Vis- and solar-active photocatalytic bi-layered films of TiO2 (layer 1) and a composite with TiO2 matrix and graphene oxide or reduced graphene oxide filler (layer 2) obtained by coupling two methods: spray pyrolysis deposition followed by spraying a diluted sol. The thin films crystallinity degree, surface morphology and elemental composition were recorded and the composites were tested in photo-degradation processes, using the standard 10 ppm methylene blue solution, under simulated UV + VIS irradiation conditions using an irradiance measured to be close to the natural one, in continuous flow process, at demonstrator scale; these results were compared with those recorded when using low irradiance values in static regime. The effect of the increase in the graphene oxide content was investigated in the concentration range 1.4%w...10%w and was found to increase the process efficiency. However, the photocatalytic efficiencies increased only by 15% at high irradiance values compared with the values recorded at low irradiance as result of the electron-hole recombination in the composite-thin film. Similar experiments were run using composites having reduced graphene oxide as filler. The interfaces developed between the matrix and the filler were discussed outlining the influence of the filler’s polarity. The thin films stability in aqueous medium was good, confirmed by the results that outlined no significant differences in the surface aspect after three successive photocatalytic cycles.

Effect of Sn content on the passivity of Ti-Ta-Sn alloys

In this work, Ti-13Ta-xSn samples were manufactured using the powder metallurgy technique with a porosity near 35 %. The microstructural analysis revealed that increased Sn content decreased the α-Ti and α’-Ti phases. Furthermore, scanning electron microscopy and X-ray photoelectron spectroscopy showed that the chemical composition of the passive oxide film was influenced by the Sn content. Moreover, the electrochemical analysis revealed that the protective properties of oxide film improved with the Sn addition.

Development and properties of wheat straw nano-holocellulose and reduced graphene oxide composite films for active packaging materials

The nano-holocellulose was obtained from wheat straw, and a series of composite films were prepared from the nano-holocellulose and reduced graphene oxide by vacuum filtration. The properties of the resultant rGO/nano-holocellulose films were researched, including morphology, XRD analysis, mechanical properties, UV-Vis transparency, contact angle, water vapor permeabilities, swelling properties, thermogravimetric analysis, and electrical conductivity. The results demonstrated that the tensile properties of the films were augmented by 639.8 %, as high as 88.70 MPa with the 8 % content of the rGO. The maximum UV transmittances of the 10 % rGO-Film in the far ultraviolet region, the middle ultraviolet region, and the near-ultraviolet region were 0.1 %, 0.4 %, and 2.1 %, respectively, which could blocked the penetration of ultraviolet light to a great extent. In addition, the hydrophilicity, water vapor permeability value, and swelling ratio of the composite films were reduced, and moreover, the composite films were endowed with the ability to conduct electricity. Compared with the 0 % rGO-Film, the contact angle of the 10 % rGO-Film was increased by about twice, and the water vapor permeability value was decreased by 10.7 %. Furthermore, 10 % rGO-Film exhibited an approximately 25-fold in conductivity compared to 1 % rGO-Film. Therefore, the nano-holocellulose based composite films have good application prospects in biodegradable packaging materials. • The composite film was prepared by nano-holocellulose and rGO. • The composite film was obtained by the vacuum filtration. • The tensile and UV resistance properties of the films were greatly enhanced by rGO. • The films were endowed with electrical conductivity by the rGO. • The composite films could be applied in packaging materials.

Free-standing vanadium oxide hydration/reduced graphene oxide film for ammonium ion supercapacitors

Aqueous ammonium-ion energy storage systems have recently gained continuous attention owing to the advantages of sustainability and environmental-friendliness in the grid-scale application. However, ammonium-ion supercapacitors are still in their infancy, and it is of great challenge in developing suitable materials for application in wearable energy storage devices. Herein, we develop a vanadium oxide hydration (V2O5·nH2O)/reduced graphene oxide (rGO) composite film (denoted as VGF) as a free-standing paper-like electrode for ammonium-ion storage, where V2O5·nH2O shows an expanded interlayer spacing and is sandwiched by rGO through chemical bonds. As a result, the designed VGF exhibits a capacitance of 600F·g−1 at 0.2 A·g−1 and good cyclability of over 10,000 cycles with a retention of 93 % using PVA/NH4Cl gel electrolyte. Meanwhile, the ammonium-ion storage mechanism in VGF electrode is further verified to be dominated by the intercalation pseudocapacitance and electric double-layer capacitance. Furthermore, the quasi-solid-state symmetric supercapacitor (SSC) has been also assembled to assess the feasibility of practical applications in wearable devices. As expected, the SSC possesses an areal capacitance of 241 mF·cm−2 at 0.1 mA·cm−2 (0.82 Wh·m−2 at 0.09 W·m−2) and an excellent cyclability of 20,000 cycles with a retention of 92 %, which is comparable to that achieved in the vanadium oxides powder-made electrodes and the SSC made of. Together with the excellent flexibility and feasibility of parallel/series combination, the VGF SSC devices shows great possibility for the applications in wearable devices, which further proves the great potential of this designed VGF free-standing electrode for ammonium-ion storage.

Analysis on Oxidation Behavior of HR3C Steel at 700°C in Water Vapor

HR3C is an advanced heat-resistant alloy, and its high-temperature oxidation resistance directly determines the service performance of the material. Therefore, exploring the high-temperature oxidation behavior of HR3C is of great significance for the theoretical research and practical application of the material. The oxidation kinetic curve, oxide film morphology, oxide film composition, and oxide film phase composition of HR3C samples in the supply state after being oxidized in water vapor at 700°C for 50h, 150h, 250h, 350h, 450h, 550h and 600h were analyzed by SEM (Scanning Electron Microscopy), EDS (Energy Dispersive Spectroscopy) and XRD (X-ray diffraction). The results show that the oxidation kinetic curve of the material conforms to the parabolic law, the oxide film first forms a lamellar oxide, and the lamellar oxide film grows alternately to form a loose and porous oxide film surface, the oxide is composed of three oxides: Fe₃O₄, FeCr₂O₄ and Fe₂O₃. The FeCr₂O₄ is a spinel compound, which can form a dense oxide film, and the diffusion coefficient of metal ions in it is small, which hinders the diffusion and mass transfer of ions, thereby improving the high temperature oxidation resistance of stainless steel. The element Cr is mainly enriched in the inner oxide layer, and the element Fe is relatively high in the outer oxide layer.

A bifunctional composite artificial solid electrolyte interphase for high stable solid-state lithium batteries

Poor interfacial compatibility between lithium (Li) metal anode and solid electrolyte is the main obstacle for solid-state Li metal batteries. To address which prefabricating an artificial solid electrolyte interphase (SEI) film on the surface of lithium anode is an effective strategy. Here, a bifunctional composite artificial SEI film with high ionic conductivity and interface compatibility is provided via in-situ forming poly-1,3-dioxolane (PDOL)/reduced graphene oxide (rGO) composite film on the surface of Li metal. The flexible high-ionic conductive PDOL improves the physical contact between the solid electrolyte and Li metal anode, and the rigid rGO effectively promotes the uniform plating of lithium ion (Li+) and suppresses the growth of Li dendrites. This rigid/flexible composite artificial SEI film not only boosts the interfacial transport of Li+, but also improves the interfacial compatibility between Li metal anode and solid electrolyte. Matching with PDOL solid electrolyte, the composite SEI film helps the Li symmetric cells to cycle stably for more than 350 h at a high current density of 0.3 mA/cm2 and an areal capacity of 0.3 mAh/cm2. Compared with the discharge specific capacity of pure Li metal anode, the discharge specific capacity of the assembled NCM622/PDOL & rGO-Li cell is increased by 17.5% at 2 C. This bifunctional composite SEI film provides a new idea for the surface modification of lithium metal anode.

In situ quantitative analysis of electrochemical oxide film development on metal surfaces using ambient pressure X-ray photoelectron spectroscopy: Industrial alloys

Ambient Pressure X-ray Photoelectron Spectroscopy combined with an electrochemical setup is used to study, in situ, the electrochemical oxide growth on an industrial Ni-Cr-Mo alloy. The native oxide film was characterized in vacuum and in water vapor at 17 mbar, and was found to be 11.4 Å thick and rich in Cr3+. In 0.1 M NaCl electrolyte, anodic growth of the oxide film at potentials up to 700 mV vs Ag/AgCl nearly doubled the thickness of the oxide film. Moreover, a transformation of the oxide composition occurred, as the oxide became enriched in Mo6+ with a chemical fingerprint more like that of pure MoO3. Both thermodynamics and kinetics of the oxidation of the alloying elements dictate the oxide film growth and composition. Furthermore, we develop the quantitative analysis of oxide composition and thickness to take into account the attenuation through the liquid water and the water vapor atmosphere. Finally, we discuss the differences between ex situ, UHV, in situ, and operando measurements. Our approach is robust, fast, simple, and suitable for systematically probing metal surfaces after aqueous exposure and electrochemical polarization, which promises wide applications for studies of solid–liquid interfaces in corrosion, batteries, fuel cells, and electrocatalysis.

Synthesis and characterization of multi-phase structure, optical and electrical properties on (Ga–Sn) oxide composite thin film by sol-gel method

The structural and optical properties of the films were investigated as a function of increasing high Gallium content amounts in the range 10–30 mol %. The composite thin films were characterized by crystallography, surface morphology, optical and electrical properties. The X-ray diffraction (XRD) method revealed that the composited thin films were multiphase in rutile tetragonal (SnO2) and β phase monoclinic (Ga2O3) type crystal structure with grown strongly in the (200) and (4‾ 01), respectively. In addition, for comparative investigate the effect of high concentration Ga incorporation on the lattice of SnO2 and the mechanism for lattice strain, Williamson-Hall method introduced. The surface morphology was investigated by Field emission Scanning Electron Microscope (FE-SEM) measurement, and it confirmed that crystallite size difference and multi-phase appear with high Ga incorporated. With UV–vis spectrometer, all (Ga–Sn) oxide composite thin films revealed a transparency of approximately 78% in the visible region. For comparative analysis of the band gap of the composite thin film, the estimated value was derived from Tauc plot, and the measured value was investigated by photoluminescence (PL). The electrical sheet resistance was measured by four-point probe method and optimized sheet resistance value of 5.66 kΩ/sq when the mixture of Ga 20 mol % concentration.

Electronic, nanomechanical and smart reversible phase transition behaviours of sputtered titanium oxide-vanadium oxide composite thin films

Crystalline vanadium oxide-titanium oxide (VO-TO) composite thin films of 197 nm are developed on quartz and silicon substrates by RF magnetron sputtering technique. A thorough structural investigation of deposited thin films is carried out by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques. Differential scanning calorimetry (DSC) and temperature-based sheet resistance measurement techniques reveals the Smart (i.e., reversible) phase transition behaviour of VO-TO films at about 45 °C. Further selective depth analysis by XPS on the VO-TO films shows the variation of the Ti doping amount along the thickness. The top region of VO-TO thin film possess lower Ti species, while beyond 50 nm thickness from the surface possess comparatively rich Ti species. This graded Ti species along the depth also results in the variation of nanomechanical properties along the depth as confirmed by nanoindentation. The simulation through the finite element approach is also carried out to depict the experimental results of nanoindentation. The nanohardness and modulus of the presently developed VO-TO composite film were measured as 6.7 GPa and 158.7 GPa, respectively at 50 nm depth. Beyond 50 nm, nanohardness and modulus were 5.6 GPa and 116.6 GPa, respectively. Further, finite element simulation predicted yield stress value of 3.52 GPa at 50 nm depth whereas higher yield stress of 4.68 GPa was predicted beyond 50 nm.

Growth behavior and corrosion resistance of graphene oxide/MgAl Layered double hydroxide coating grown on micro-arc oxidation film of magnesium alloys

The MgAl Layered double hydroxides (LDHs)/graphene oxide (GO) composite film was fabricated in situ on the micro-arc oxidation (MAO) film (MAO/LG) of AZ31 magnesium alloy in one step by hydrothermal chemical conversion method. The growth behavior and corrosion properties of LG films were investigated. The results show that the chemical structure, composition and morphology of the LG film will gradually change with the extension of the hydrothermal treatment time based on using the self-dissolved cation (Mg2+ and Al3+) in the MAO film as the source of growing LDHs without introducing any external metal cations. The potentiodynamic polarization showed that the MAO/LG-12 h coating (1.28 × 10−9 A/cm2) after in situ growth for 12 h was more corrosion resistant than the MAO coating (8.49 × 10−6 A/cm2). The synergistic effect of GO and LDHs can significantly improve the corrosion protection ability of MAO coating. In addition, the transition process of the growth behavior of the LG film layer on the MAO coating is explained in detail.

Development of polymethylmethacrylate/reduced graphene oxide composite films as thermal interface materials

AbstractWith the miniaturization and integration of electronics into more powerful but smaller functional devices, major challenges arise. One of them is to efficiently dissipate the significant amount of thermal energy produced by these electronic devices. This requires interface materials with good thermal management properties. Reduced graphene oxide has attracted a lot of interest in this area due to its good thermal conductivity, similar with those of pristine graphene. In this work, polymethylmethacrylate/reduced graphene oxide (PMMA/RGO) composite thin films have been generated by drop casting mixtures of PMMA solutions and RGO suspensions, all prepared in N,N‐dimethylformamide (DMF) solvent. Raman, SEM and AFM investigations confirmed that homogenous PMMA/RGO composite thin films have been obtained, with RGO being uniformly distributed in the blending. Further measurements demonstrated that the thermal conductivity of RGO/PMMA composites increased with the concentration of RGO in the polymeric mixture: for the highest RGO content, the thermal conductivity increased by 210%, with no important modifications of electrical resistivity. These results are very promising for the development of new thermal interface materials based on PMMA/RGO composites to be used, for instance, in automotive industry.

Effect of oxidation treatment on the structure and composition of oxide film on Al-Mg-Sc alloy surface and microstructure of Al substrate near interface

The oxidation behavior of Al-Mg-Sc alloy at 200 °C was investigated. The structure and composition of oxide film on Al-Mg-Sc alloy surface were analyzed by XRD and ARXPS. The microstructure evolution of Al substrate near the interface between Al-Mg-Sc alloy and oxide film was explored by EBSD and TEM. The experimental results indicated that after oxidation treatment at 200 °C, the oxide film was mainly composed of MgO, Al2O3 and a small amount of MgAl2O4. MgAl2O4 was mainly distributed at the bottom of the oxide film and the formation of MgAl2O4 was followed by formation of MgO. Meanwhile, the grains rotated, and part of the LAGBs were transformed into HAGBs with many poorly matched atoms. Mg atoms could quickly diffuse to the grain boundary and the surface through dislocation channels to participate in the oxidation reaction, which favoured the formation of MgAl2O4 at the interface.

The effect of argon ion etching treatments on anodic oxide film growth and the electrochemical properties of tantalum

The aim of present paper was to improve the anticorrosive properties of tantalum. Herein, the formation of tantalum oxide film via an argon ion etching pretreatment step and anodic oxidation is reported. The surface morphologies of etched tantalum investigated using scanning electron microscopy. The composition and corrosion resistance of the tantalum oxide film was characterized using X-ray photoelectron spectroscopy and an electrochemical workstation, respectively. The effects of vacancy defects and O atom adsorption on the on Ta (110), (200) and (211) surfaces have been investigated based on first-principles calculations to simulate the etched surface. The experimental results showed that the etched tantalum had a relatively clean surface with fine pores, which promoted the formation of an anodization film to 131.53 nm. The corrosion resistance of tantalum was obviously improved by etching followed by anodization, and the highest corrosion potential of 0.133 V and relatively low corrosion current density of 1.016 μA cm–2 were observed. Furthermore, first principle calculations revealed that vacancy defects increased the activity of the tantalum surface and enhanced the adsorption of oxygen, thereby promoting the formation of oxide film. Among all these defective surfaces, O atom adsorption on the (110) surface exhibited relatively a high adsorption energy of −519.66 kJ/mol and charge transfer of −1.310 e, followed by O atoms on the (200) and (211) surfaces showing an enhanced adsorption energy of −487.33 and −494.27 kJ/mol, and charge transfer of 1.255 and 1.194 |e |, respectively. This work demonstrated an effective argon ion etching pretreatment step to promote the formation of oxide film, which improved the corrosion behavior of tantalum.

Low-frequency noise and impedance spectroscopy of device structures based on perovskite-graphene oxide composite films

Low-frequency noise and impedance spectroscopy of device structures based on perovskite-graphene oxide composite films

Cosputtered SnO2–ZnO composite nanofilms with improved dual function

AbstractSnO2–ZnO composite thin films were grown by radio‐frequency and direct‐current cosputtering of ceramic ZnO and metallic Sn targets, respectively. During the cosputtering film growth, the SnO2 matrix sputtering power was fixed at 20 W, while the additive ZnO sputtering power was varied in the range of 40–80 W. Structural and compositional analysis results showed that the ZnO sputtering power increased the relative ZnO phase content in the composite film and its surface grain size. Compared to the single‐constituent compounds, the as‐synthesized SnO2–ZnO composite films exhibited enhanced photoelectrocatalytic performances for the degradation of methyl orange dyes under irradiation. The SnO2–ZnO composite film obtained at a ZnO sputtering power of 60 W (SZ60; Zn/Sn = 11.2%) exhibited the highest photoelectrocatalytic activity among the various samples. In addition, SZ60 exhibited superior ethanol gas‐sensing performances among the various thin‐film sensors. Owing to the formation of a suitable number of SnO2/ZnO heterojunctions, SZ60 exhibited a highly efficient photo‐induced charge separation and appropriate potential barrier height to improve the gas‐sensing ability. The experimental results demonstrate a promising approach to design oxide composite films with desirable photoelectrocatalytic and gas‐sensing functions by controlling the relative content of ZnO and SnO2 in the composite film through a cosputtering process.

Tailoring the microstructure and enhancing the corrosion resistance of extruded dilute Mg-0.6Al-0.5Mn-0.25Ca alloy by adding trace Ce

The effect of trace Ce addition on the microstructure evolution and corrosion behavior of dilute Mg-0.6Al-0.5Mn-0.25Ca-xCe (x = 0.1–0.3 wt%) alloys were investigated using immersion tests and electrochemical measurements. The Ce addition caused the formation of Al8Mn4Ce and Al11Ce3, which were less noble than Al8Mn5. Strikingly, the alloy containing 0.3 wt% Ce exhibited the lowest average corrosion rate of 4.13 mm y−1, which was 6.5 times lower than that of Ce-free alloy. The outstanding anti-corrosion properties were attributed to the low potential difference between Ce-containing phases and matrix, the compact composite oxide film (MgO-CeO2-Al2O3), and the enrichment of Fe in Ce-containing phases.

Preparation technology and properties of a thin anodic oxide composite film on the surface of an aluminum alloy foil

This paper presents the process of preparing a phosphoric-acid thin anodic oxide composite film on an 18 μm aluminum alloy foil. The parameters of anodizing were adjusted to obtain a thin anodic oxide film, and then the nano-pores of the film were sealed by electrodeposited silane doped with Y3+. A dense and uniform oxide-organic composite film (called TAO-Si@Y film) with a thickness of only about 275 nm was successfully prepared. The structure, morphology, composition and corrosion resistance of the composite film were investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), energy spectroscopy (EDS), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and neutral salt spray. The silanol groups of the silane reacted with the thin anodic oxide film to form Al-O-Si. The TAO-Si@Y film had a corrosion current density icorr of 9.18 × 10−9 A cm−2 and a low-frequency impedance modulus |Z|0.01 of 2.26 × 106 Ω cm2, which could provide long-term corrosion protection to the Al foil substrate. Furthermore, the influence of the Y3+ doping in silane solution on the composite film was also discussed.

Electrical characterisation of photosensitive Si/W–Ge oxide composite heterojunction

Tungsten-germanium (W–Ge) oxide composite thin film was grown on the p-type Si wafer which already has an Al ohmic contact, with the co-deposition technique by using magnetron sputter method and Al/Si/W–Ge oxide composite heterojunction was fabricated. The active layer surface analysis was determined by Scanning electron microscopy (SEM) and it was observed that it has a homogeneous surface morphology. The distribution and weight percentage of elements that formed to thin film was determined by Energy dispersive X-ray spectrometry (EDX). It was found that W, Ge and O are homogenously distributed in the film. Electrical properties of fabricated heterojunction were characterised under forward and reverse bias at different light intensity. It was obtained that diode ideality factor (n) and series resistance (Rs) dropped up to 2.98 and 5Ω, respectively and also barrier height (∅b) took the values between 0.38 to 0.32eV. Additionally, photocurrent, photoresponsivity, photosensitivity and photovoltaic parameters of the heterojunction were calculated under different light intensity. It was determined that the heterojunction exhibited typical photodiode behaviour and the maximum fill factor (FF) value was 0.3084 under 60mW/cm2 light intensity.

Enhanced visible-light photocatalytic activity of rGO-ZnO composite thin films prepared by SILAR method

ABSTRACTThis study reported the first-time preparation of reduced graphene oxide (rGO) and zinc oxide (ZnO) composite (rGO-ZnO) thin films through successive ionic layer adsorption and reaction (SILAR) method. The effects of rGO and heat treatment on the structural, morphological, chemical, optical, vibrational and photocatalytic properties of composite films were investigated. The structural results showed that ZnO and rGO-ZnO thin films could be obtained without heat treatment. The rGO-ZnO composite showed improved crystallinity and homogeneity compared to ZnO, with formation of flower-like structures. The presence of graphene derivatives in the composite films was validated using Raman spectroscopy. Chemical composition analysis showed an increase in the carbon content in rGO-ZnO composite. Optical transmittance in the visible range was reduced from 90% for ZnO to 51% for rGO-ZnO. Moreover, the bandgap energy of ZnO decreased from 3.33 to 3.04 eV with the presence of rGO and heat treatment. The rGO-ZnO composite thin films exhibit enhanced visible-light photocatalytic discoloration of Orange G dye, which is attributed to bandgap narrowing with improved visible light response and charge separation. The approach described here provides a simple and efficient way to synthesise rGO-ZnO composite thin films with potential applications for a wide range of environmental issues.