Efficiency and Mechanism of Phosphorus Removal by Coagulation of Iron-manganese Composited Oxide

Iron-manganese composited oxide（FeMnO） was prepared with potassium permanganate and ferrous salt. Interface performance, charge property and structure topography of the FeMnO were investigated. Coagulation efficiency and pollution removal mechanism of the FeMnO were approached. Results show that the main compositions of the FeMnO are δ-manganese dioxide and ferric hydroxide. The specific surface area is about 146.22 m^2/g. The FeMnO contains rich hydroxyl with extremely strong adsorption action and chemical adsorption activity. The zero charge point of the oxide in pure water is about 8.0 of pH value. Under neutral pH value conditions, the FeMnO particle surface carried positive charges. The FeMnO particles are quasi-spherical micro-particles with irregular sizes adjoined each other to form net construction. Phosphorus removal efficiency of the FeMnO is remarkable, the total dissoluble phosphorus of settled water can be reduced below detecting level（0.3 μtg/L） at a FeMnO dosage of 6 mg/L, and total phosphorus below detecting level at a FeMnO dosage of 10 mg/L, for water samples containing total phos- phorus of 1281.70 μg/L and total dissoluble phosphorus of 1187.91 μtg/L. The mechanism of effective coagulation for phosphorus removal is combined results of multiple actions of adsorption, charge neutralization, adsorption/bridging and so on.

Oxide film on bubble surface of aluminum foams produced by gas injection foaming process

Based on A356 aluminum alloy,aluminum foams were prepared by gas injection foaming process with pure nitrogen,air and some gas mixtures.The oxygen volume fraction of these gas mixtures varied from 0.2%to 8.0%.Optical microscopy,scanning electron microscopy（SEM） and Auger electron spectroscopy（AES） were used to analyze the influence of oxygen content on cell structure,relative density,macro and micro morphology of cell walls,coverage area fraction of oxide film,thickness of oxide film and other aspects.Results indicate that the coverage area fraction of oxide film on bubble surface increases with the increase of oxygen content when the oxygen volume is less than 1.2%.While when the oxygen volume fraction is larger than 1.6%,an oxide film covers the entire bubble surface and aluminum foams with good cell structure can be produced.The thicknesses of oxide films of aluminum foams produced by gas mixtures containing 1.6%-21%oxygen are almost the same.The reasons why the thickness of oxide film nearly does not change with the variation of oxygen content and the amount of oxygen needed to achieve 100%coverage of oxide film are both discussed.In addition,the role of oxide film on bubble surface in foam stability is also analyzed.

Fabrication of titanium oxide films at low temperature from aqueous solution

Titanium oxide thin films were prepared on self-assembled monolayers-coated silicon substrate using layer-by-layer self-assembly method and chemical bath deposition from an aqueous solution. The effects of temperature on structural properties, thickness and morphologies of titanium oxide thin films were investigated. The results show that the absorption peak of peroxo complexes of titanium at 410 nm decreases gradually with increasing the temperature. The deposited films consisting of titanium oxide nanocrystals are believed to be fully amorphous by XRD. Titanium oxide thin films fabricated at 60 °C for 2 h are continuous, dense and homogeneous with a size in the range of 20-40 nm by SEM. The chemical compositions of deposited thin films were studied by EDS, and the mole ratio of O to Ti is 2.2：1.

Oxidation kinetics of oxide film on bubble surface of aluminum foams produced by gas injection foaming process

In the range of 620？710 °C, air was blown into A356 aluminum alloy melt to produce aluminum foams. In order to study the influence of temperature on the thickness of oxide film on bubble surface, Auger electron spectroscopy （AES） was used. Based on the knowledge of corrosion science and hydrodynamics, two oxidation kinetics models of oxide film on bubble surface were established. The thicknesses of oxide films produced at different temperatures were predicted through those two models. Furthermore, the theoretical values were compared with the experimental values. The results indicate that in the range of 620？710 °C, the theoretical values of the thickness of oxide film predicted by the model including the rising process are higher than the experimental values. While, the theoretical values predicted by the model without the rising process are in good agreement with the experimental values, which shows this model objectively describes the oxidation process of oxide film on bubble surface. This work suggests that the oxidation kinetics of oxide film on bubble surface of aluminum foams produced by gas injection foaming process follows the Arrhenius equation.

EFFECT OF ELECTRODEPOSITED Cr_2O_3 OXIDE FILM ON THE OXIDATION OF Fe_3Al

A uniform, dense and defect free Cr2O3 thin film, which is amorphous at ambient temperature, was applied on the surface of intermetallic Fe3Al by electrodeposition reaction sintering, and the effect of this film on the oxidation of Fe3Al at 900 ℃ in air was studied. The films and the oxide scales were analyzed by TEM, EDAX,SEM and XRD.It is proved that, by surface applied Cr2O3 thin film,a continuous, protective,fine grained α-Al2O3 scale was formed on Fe3Al. As a result, the adherence of the scale and oxidation resistance of Fe3Al were improved.

Effects of Atomic Oxygen Irradiation on Transparent Conductive Oxide Thin Films

Transparent conductive oxide （TCO） thin film is a kind of functional material which has potential applications in solar cells and atomic oxygen （AO） resisting systems in spacecrafts. Of TCO, ZnO：Al （ZAO） and In2O3：Sn （ITO） thin films have been widely used and investigated. In this study, ZAO and ITO thin films were irradiated by AO with different amounts of fluence. The as-deposited samples and irradiated ones were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and Hall-effect measurement to investigate the dependence of the structure, morphology and electrical properties of ZAO or ITO on the amount of fluence of AO irradiation. It is noticed that AO has erosion effects on the surface of ZAO without evident influences upon its structure and conductive properties. Moreover, as the amount of AO fluence rises, the carrier concentration of ITO decreases causing the resistivity to increase by at most 21.7%.

Effect of RF power on the properties of transparent conducting zirconium-doped zinc oxide films prepared by RF magnetron sputtering

Transparent and conducting zirconium-doped zinc oxide films with high transparency and relatively low resistivity have been successfully prepared by radio frequency （RF） msgnetron sputtering at room temperature, The RF power is varied from 75 to 150 W. At first the crystallinity and conductivity of the film are improved and then both of them show deterioration with the increase of the RF power, The lowest resistivity achieved is 2.07 × 10^-3Ωcm at an RF power of 100W with a Hall mobility of 16cm^2V^-1s^-1 and a carrier concentration of 1.95 × 10^20 cm^-3. The films obtained are polycryetalline with a hexagonal structure and a preferred orientation along the c-axis, All the films have a high transmittance of approximately 92% in the visible range. The optical band gap is about 3.33 eV for the films deposited at different RF powers.

A novel,environmentally friendly and facile method for oxidative energy storage in nickel hydroxide film electrodes

The oxidative energy storage behaviors of a designed novel system comprising a nickel hydroxide film electrode and an oxygen-reducing platinum cathode were investigated by various electrochemical techniques. The structure and morphology of samples were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD） analysis. It is found that the oxidative energy storage in the Ni（OH）2 electrodes can be obviously enhanced in the coupling system containing the cathode electrolytes with higher oxygen content or lower pH value. The results of the oxidation-discharge cycle tests show that the Ni（OH）2 film electrode oxidized in the coupling system with 1.0 mol/L Na2SO4 （pH=2） as cathode electrolyte for 600 s presents discharge capacities of 79.0 mC/cm2 at the first cycle and 97.9 mC/cm2 at the 12th cycle, suggesting the excellent reversibility of the investigated oxidative energy storage and conversion system.

Effects of acetic acid on microstructure and electrochemical properties of nano cerium oxide films coated on AA7020-T6 aluminum alloy

Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and potentiodynamic polarization methods. It has been found that by increasing the acetic acid/CeCl3·7H2O molar ratio, high uniform and crack-free films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.

Spontaneous Cracking of Graphite Oxide Sheet on Oxygen Deficient ZnO Film

Graphite oxide （GO） is an important material of wide applications. Owing to its good mechanical property, the GO sheet is always expected to be stable and remains flat on various substrates. Here we demonstrate for the first time an unexpected behavior of the GO sheet on oxygen deficient ZnO film, namely the spontaneous cracking of the entire GO sheet into many small pieces. This unusual behavior has been carefully investigated by a series of control experiments and SEM, XPS and PL measurements. It is anticipated that the oxygen vacancies in the oxygen deficient ZnO film can annihilate epoxy groups of the GO sheet, resulting in the unzipping of the aligned epoxy groups on GO sheet. A prototype of the white light detector made from the cracked GO sheet is fabricated and the device demonstrates high stability and good reproducibility.

Fabrication and characterization of anodic oxide films on a Ti-10V-2Fe-3Al titanium alloy

Anodic oxide films of the titanium alloy Ti-10V-2Fe-3Al in ammonium tartrate electrolyte without hydrofluoric acid or fluoride were fabricated. The morphology, components, and microstructure of the films were characterized by scanning electron microscopy （SEM）, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, and Raman spectroscopy. The results showed that the films were thick, uniform, and nontransparent. Such films exhibited sedimentary morphology, with a thickness of about 3 μm, and the pore diameters of the deposits ranged from several hundred nanometers to 1.5 μm. The films were mainly titanium dioxide. Some coke-like deposits, which may contain or be changed by OH, NH, C-C, C-O, and C=O groups, were doped in the films. The films were mainly amorphous with a small amount of anatase and rutile phase.

Ultraviolet photodetectors based on wide bandgap oxide semiconductor films

Ultraviolet(UV) photodetectors have attracted more and more attention due to their great potential applications in missile tracking, flame detecting, pollution monitoring, ozone layer monitoring, and so on. Owing to the special characteristics of large bandgap, solution processable, low cost, environmentally friendly, etc., wide bandgap oxide semiconductor materials, such as ZnO, ZnMgO, Ga_2O_3, TiO_2, and Ni O, have gradually become a series of star materials in the field of semiconductor UV detection. In this paper, a review is presented on the development of UV photodetectors based on wide bandgap oxide semiconductor films.

Wear-resisting Oxide Films for 900℃

A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring oxide film in order to improve its tribological properties. Improvement is needed at low temperatures where the oxide film, previously formed at high temperature, spalls due to stresses induced by sliding. Experiments with Ti, W and Ta additions show a beneficial effect when added to Ni and Ni-base alloys. Low friction can be maintained down to 100℃ from 900℃. For unalloyed Ni friction and surface damage increases at 400℃ to 500℃. Two new alloys were perpared based on the beneficial results of binary alloys and ZrO2 diffusion in Ni.Low friction at temperature above 500℃ and reasonable values (0.32~0.42) at low temperature are obtained.

Properties of oxide films grown on 25Cr20Ni alloy in air-H_2O and H_2-H_2O atmospheres

The oxidation kinetics,surface morphology and phase structure of oxide films grown on 25Cr20Ni alloy in air-H2O and H2-H2O atmospheres at 900 ℃ for 20 h were investigated.The anti-coking performance and resistance to carburization of the two oxide films were compared using 25Cr20Ni alloy tubes with an inner diameter of 10 mm and a length of 850 mm in a bench scale naphtha steam pyrolysis unit.The oxidation kinetics followed a parabolic law in an air-H2O atmosphere and a logarithm law in a H2-H2O atmosphere in the steady-state stage.The oxide film grown in the air-H2O atmosphere had cracks where the elements Fe and Ni were enriched and the un-cracked area was covered with octahedral-shaped MnCr2O4 spinels and Cr1.3Fe0.7O3 oxide clusters,while the oxide film grown in the H2-H2O atmosphere was intact and completely covered with dense standing blade MnCr2O4 spinels.In the pyrolysis tests,the anti-coking performance and resistance to carburization of the oxide film grown in the H2-H2O atmosphere were far better than that in the air-H2O atmosphere.The mass of coke formed in the oxide film grown in the H2-H2O atmosphere was less than 10％ of that in the air-H2O atmosphere.The Cr1.3Fe0.7O3 oxide clusters converted into Cr23C6 carbides and the cracks were filled with carbon in the oxide film grown in the air-H2O atmosphere after repeated coking and decoking tests,while the dense standing blade MnCr2O4 spinels remained unchanged in the oxide film grown in the H2-H2O atmosphere.The ethylene,propylene and butadiene yields in the pyrolysis tests were almost the same for the two oxide films.

Surface oxidation of vanadium dioxide films prepared by radio frequency magnetron sputtering

This paper reports that the thermochromic vanadium dioxide films were deposited on various transparent substrates by radio frequency magnetron sputtering, and then aged under circumstance for years. Samples were characterized with several different techniques such as x-ray diffraction, x-ray photoelectron spectroscopy, and Raman, when they were fresh from sputter chamber and aged after years, respectively, in order to determine their structure and composition. It finds that a small amount of sodium occurred on the surface of vanadium dioxide films, which was probably due to sodium ion diffusion from soda-lime glass when sputtering was performed at high substrate temperature. It also finds that aging for years significantly affected the nonstoichiometry of vanadium dioxide films, thus inducing much change in Raman modes.

Surface Analysis of Chemical Stripping Titanium Alloy Oxide Films

The chemical stripping method of titanium alloy oxide films was studied. An environment friendly solution hydrogen peroxide and sodium hydroxide without hydrofluoric acid or fluoride were used to strip the oxide films. The morphologies of the surface and cross-section of the oxide films before and after the films stripping were characterized by using scanning electron microscopy （SEM）. The microstructure and chemical compositions of the oxide films before and after the films stripping were investigated by using Raman spectroscopy （Raman） and X-ray photoelectron spectroscopy （XPS）. It was shown that the thickness of the oxide film was in the range of 5-6 μm. The oxide films were stripped for 2 to 8 min in the solution. Moreover, the effect of the stripping time on the efficiency of the film stripping was investigated, and the optimum stripping time was between 6-8 min. When the stripping solution completely dissolved the whole film, the α/β microstructure of the titanium alloy Ti-10V-2Fe-3Al was partly revealed. The stripping mechanism was discussed in terms of the dissolution of film delamination. The hydrogen peroxide had a significant effect on the dissolution of the titanium alloy anodic oxide film. The feasibility of the dissolution reaction also was evaluated.

Morphology and growth of porous anodic oxide films on Ti-10V-2Fe-3Al in neutral tartrate solution

Porous anodic oxide films were fabricated galvanostatically on titanium alloy Ti-10V-2Fe-3Al in ammonium tartrate solution with different anodizing time.Scanning electron microscopy(SEM) and field emission scanning electron microscopy(FE-SEM) were used to investigate the morphology evolution of the anodic oxide film.It is shown that above the breakdown voltage,oxygen is generated with the occurrence of drums morphology.These drums grow and extrude,which yields the compression stress.Subsequently,microcracks are generated.With continuous anodizing,porous oxides form at the microcracks.Those oxides grow and connect to each other,finally replace the microcrack morphology.The depth profile of the anodic oxide film formed at 1 800 s was examined by Auger electron spectroscopy(AES).It is found that the film is divided into three layers according to the molar fractions of elements.The outer layer is incorporated by carbon,which may come from electrolyte solution.The thickness of the outer layer is approximately 0.2-0.3 μm.The molar fractions of elements in the intermediate layer are extraordinarily stable,while those in the inner layer vary significantly with sputtering depth.The thicknesses of the intermediate layer and the inner layer are 2 μm and 1.0-1.5 μm,respectively.Moreover,the growth mechanism of porous anodic oxide films in neutral tartrate solution was proposed.

Freestanding oxide membranes:synthesis,tunable physical properties,and functional devices

The study of oxide heteroepitaxy has been hindered by the issues of misfit strain and substrate clamping,which impede both the optimization of performance and the acquisition of a fundamental understanding of oxide systems.Recently,however,the development of freestanding oxide membranes has provided a plausible solution to these substrate limitations.Single-crystalline functional oxide films can be released from their substrates without incurring significant damage and can subsequently be transferred to any substrate of choice.This paper discusses recent advancements in the fabrication,adjustable physical properties,and various applications of freestanding oxide perovskite films.First,we present the primary strategies employed for the synthesis and transfer of these freestanding perovskite thin films.Second,we explore the main functionalities observed in freestanding perovskite oxide thin films,with special attention to the tunable functionalities and physical properties of these freestanding perovskite membranes under varying strain states.Next,we encapsulate three representative devices based on freestanding oxide films.Overall,this review highlights the potential of freestanding oxide films for the study of novel functionalities and flexible electronics.

Photovoltaic properties of Cu_2O-based heterojunction solar cells using n-type oxide semiconductor nano thin films prepared by low damage magnetron sputtering method

We improved the photovoltaic properties of Cu_2O-based heterojunction solar cells using n-type oxide semiconductor thin films prepared by a sputtering apparatus with our newly developed multi-chamber system. We also obtained the highest efficiency(3.21%) in an AZO/p-Cu_2O heterojunction solar cell prepared with optimized pre-sputtering conditions using our newly developed multi-chamber sputtering system. This value achieves the same or higher characteristics than AZO/Cu_2O solar cells with a similar structure prepared by the pulse laser deposition method.

Corrosion behaviors of thermally grown oxide films on Fe-based bulk metallic glasses

Oxide films formed on the surfaces of Fe-based bulk metallic glasses in the temperature range between 373 K and 573 K were characterized and their effects on the corrosion behaviors were investigated by microstructural and electrochemical analysis. The oxide film formed at 573 K is iron-rich oxide and it exhibits an n-type semiconductor at a higher potential than 0.35 V and a p-type semiconductor at a lower potential than 0.35 V. Capacitance measurements show that the donor density decreases with the increase in oxidation temperature, while the thickness of the space charge layer increases with the oxidation temperature rising. The result of immersion tests shows that the mass loss rate increases with the oxidation temperature rising. Therefore, the correlation between microstructure and corrosion resistance needs to be proposed because the corrosion resistance is deteriorated with the development of the oxide films.