Q235碳钢在不同浓度和温度的十二硫醇中的腐蚀行为

目前,研究金属材料在十二硫醇中腐蚀行为的报道较少。将Q235碳钢挂片于不同浓度和温度的十二硫醇中进行腐蚀,并计算腐蚀速率;采用扫描电镜(SEM)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)对Q235碳钢表面腐蚀形貌和成分进行了观察和分析,并研究了腐蚀机制。结果表明:Q235碳钢在十二硫醇中的腐蚀速率和腐蚀机制与十二硫醇在Q235碳钢表面的吸附和覆盖状况密切相关,当十二硫醇的浓度从低到高变化时,其在Q235碳钢表面的吸附量和覆盖度也表现出从低到高的特征,Q235碳钢从局部腐蚀转变为均匀腐蚀;Q235碳钢在十二硫醇中的腐蚀速率随着温度的升高而逐渐增大,且两者之间基本满足线性关系;Q235碳钢表面腐蚀产物呈多裂纹的疏松结构,主要物相成分为Fe_2O_3、Fe_3O_4、FeS和FeS_2。     

Bandgap determination of P(VDF-TrFE) copolymer film by electron energy loss spectroscopy

The ferroelectric β of poly(vinylidene fluoride trifluoroethylene), P(VDF-TrFE) is confirmed for 100 nm thickness spin coated copolymer film. The homogeneous coverage of the copolymer film is investigated by the help of X-ray photoelectron spectroscopy (XPS). Most importantly, the existing bandgap in the crystalline phase of the copolymer is determined directly from the electron energy loss spectroscopy (EELS).     

The influence of chemistry on the adhesion at the interface of carbon/epoxy composites

A method of determining surface acidity has been developed by using adsorption isotherms to interpret the uptake of labelling ions from solution. X-Ray photoelectron spectroscopy (XPS) can be used to measure the concentration of ions taken up directly so that gas adsorption isotherms can be applied and a monolayer coverage calculated. Concentration of acidity can be calculated if the number of ions per acid group is known. For the particular fibre tested the surface acidity correlated well with interfacial adhesion and increased with surface treatment up to the optimum adhesion level determined by single-fibre fragmentation and pull-out tests.     

Titanium monoxide ultra-thin coatings evaporated onto polycrystalline copper films

We evaporated polycrystalline copper thin films of thickness between 10 and 100 nm on silicon substrates with their native oxide under ultra-high-vacuum conditions. Some of them were exposed to air for a period ranging from 1 day to 2 weeks. X-ray photoelectron spectroscopy (XPS) revealed a clean copper surface with a trace of oxygen. These films that were exposed to air presented oxides in the state Cu(II), the amount of CuO depended on the time that the film was exposed to air. Subsequently, we deposited TiO ultra-thin films on polycrystalline copper substrates. Both these thin films were formed by electron beam evaporation. XPS spectra showed that the surface of the titanium monoxide (TiO) films was contamination-free. An evaporation of 0.3 nm of TiO reduced the native oxide of the copper substrates from Cu(II) to Cu(I) or Cu(0) and transformed the TiO into TiO₂ at the interface. Low-energy ion spectroscopy showed that the complete coverage of the substrates depends on the thickness of the copper films. For 10 nm copper thin films the complete coverage occurred at 1.5 nm of TiO, and for 100 nm it occurred at 2.0 nm of TiO. In samples exposed to air, the complete coverage occurred at a film thickness slightly higher than those treated under ultra-high-vacuum conditions.     

Characterization of phosphorus oxinitride (PON) gate insulators for InP metal-insulator-semiconductor devices

A new gate-insulating film consisting of phosphorus oxinitride (PON) was formed on an (n)InP surface by vapour transport technique. The substrate temperature was in the range of 280–350°C. The deposited films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). The interfacial properties of phosphorus oxinitride/(n)InP metal-insulator-semiconductor were investigated. The minimum value of the interface states density distribution (D_it), evaluated from high-frequency capacitance-voltage (C-V) measurement was 1.2 × 10¹¹ eV⁻¹ cm⁻² at about 0.48 eV below the conduction band edge of Inp.     

Surface treatments of indium tin oxide films by using high density plasma

We investigated the effects of various surface treatments on the work function and chemical composition of an indium tin oxide (ITO) surface. Ultraviolet photoelectron spectroscopy (UPS) was used to measure the work function of ITO. X-ray photoelectron spectroscopy (XPS) was used to study the electron structures of ITO surface. We performed surface treatments on ITO using O₂ plasma and HCl solution. Our UPS/XPS analysis indicates increases in the work functions by O₂ plasma treatments. It is known that the Fermi energy level is controlled by the donor concentration, and thus the Fermi energy level is shifted toward the valence band minimum.     

A method for preparing ferric activated carbon composites adsorbents to remove arsenic from drinking water

Iron oxide/activated carbon (FeO/AC) composite adsorbent material, which was used to modify the coal-based activated carbon (AC) 12 x 40, was prepared by the special ferric oxide microcrystal in this study. This composite can be used as the adsorbent to remove arsenic from drinking water, and Langmuir isotherm adsorption equation well describes the experimental adsorption isotherms. Then, the arsenic desorption can subsequently be separated from the medium by using a 1% aqueous NaOH solution. The apparent characters and physical chemistry performances of FeO/AC composite were investigated by X-ray diffraction (XRD), nitrogen adsorption, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Batch and column adsorption experiments were carried out to investigate and compare the arsenic removal capability of the prepared FeO/AC composite material and virgin activated carbon. It can be concluded that: (1) the main phase present in this composite are magnetite (Fe(3)O(4)), maghemite (gamma-Fe(2)O(3)), hematite (alpha-Fe(2)O(3)) and goethite (alpha-FeO(OH)); (2) the presence of iron oxides did not significantly affect the surface area or the pore structure of the activated carbon; (3) the comparisons between the adsorption isotherms of arsenic from aqueous solution onto the composite and virgin activated carbon showed that the FeO/AC composite behave an excellent capacity of adsorption arsenic than the virgin activated carbon; (4) column adsorption experiments with FeO/AC composite adsorbent showed that the arsenic could be removed to below 0.01 mg/L within 1250 mL empty bed volume when influent concentration was 0.5mg/L.     

Characterization of gold nanoparticle binding to microtubule filaments

Microtubule (MT) protein filaments were used as templates for fabricating Au nanowires as a bottom-up approach for fabricating building blocks for future integrated circuits. Photochemical reduction methods were employed to form Au nanoparticles which bind and uniformly cover the MT filaments. Synthesis of the MT-templated Au nanowires was characterized using UV/vis spectroscopy and transmission electron microscopy (TEM). In addition, binding between the MT filaments and Au nanoparticles was investigated using surface enhanced Raman spectroscopy (SERS) and X-ray photoelectron spectroscopy (XPS) to establish the nature of the binding sites. A variety of functional groups were identified by SERS to interact with the Au including imidazole, sulfur, aromatic rings, amine, and carboxylate. The imidazole ring in the histidine is the most prominent functional group for Au binding. The results from these studies provide better understanding of the binding between Au and the biotemplate and give insight concerning methods to improve Au coverage for MT-templated Au nanowires.     

Temperature effects on the chemical composition of nickel-phosphorus alloy thin films

Electroless Ni-P (EN) alloys are widely used as coating materials. Their properties depend on the level of phosphorus present and the extent of thermal treatment. We report the results of two complimentary electronic structure techniques, X-ray absorption near edge structure (XANES) and X-ray photoelectron spectroscopy (XPS), and the site-specific surface chemistry in EN alloys of different phosphorus compositions and thermal treatments. In XANES experiment, absorption at the Ni L_3,2 edge and the P K edge were measured and the P 2p, Ni 2p, and Ni 3p bands were measured by XPS. Heating EN alloys to high temperatures result in a competitive reaction between phosphorus and nickel on the surface for oxygen. There is an increase in the level of phosphates and other forms of phosphorus oxides and a decrease in the oxidized nickel on the surface of the EN alloy thin film. Changes in the electronic structure and chemical composition in the bulk of the EN alloy are not obvious.     

pH-Dependent gold nanoparticle self-organization on functionalized Si/SiO2 surfaces

The self-organization of citrate- and acrylate-stabilized gold nanoparticles onto SiO₂/hydroxyl-, amino- and nitro-terminated surfaces was investigated as a function of pH. Bare clean Si/SiO₂ substrates were used as the SiO₂/hydroxyl-terminated surfaces and self-assembled monolayers (SAM) of (3-aminopropyl)trimethoxysilane (APTMS) and 3-(4-nitrophenoxy)-propyltrimethoxysilane (NPPTMS) on Si/SiO₂ were employed as the amino- and nitro-terminated surfaces, respectively. All the surfaces were fully characterized by contact angle, atomic force microscopy (AFM), ellipsometry and X-ray photoelectron spectroscopy (XPS). Citrate- and acrylate-stabilized gold nanoparticle stability was also investigated as a function of pH by UV–visible absorption spectroscopy and Z-potentiometry. The gold nanoparticle surface coverage of the substrates was independently estimated by AFM and XPS. The results show that colloid deposition on bare SiO₂/OH surfaces and on NPPTMS monolayers is negligible with the exception of acrylate-stabilized gold nanoparticles which were found to be immobilized on nitro-terminated surfaces at pH lower than 3.5. Nevertheless, APTMS monolayers interact strongly with citrate- and acrylate-stabilized gold nanoparticles exhibiting a dependence of the surface coverage from the pH of the colloidal solution.     

Orientation of ethyl mercaptan on Cu(111) surface

X-Ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS) studies have been performed on ethyl mercaptan adsorbed on a clean Cu(111) surface at 85 K. At submonolayer coverage (0.36 ML), two different states of sulfur (thiolate) are identified with the aid of XPS investigations. Polarization dependence of S K-edge NEXAFS of the submonolayer phase indicates that the S---C bond for the two thiolate phases are tilted 33±7° and 30±7° from the surface.     

Improvement of Ge/Pd/GaAs ohmic contact by In layer

The presented work describes behaviour of contact structures of the Ge/Pd type with the In layer deposited on the surface of the GaAs substrate plate prior to the metallization. The most suitable structure by contact resistivity and thermal stability is Ge(40 nm)/Pd(20 nm)/In(22 nm). This structure shows minimal contact resistivity 2 × 10⁻⁶ Ωcm². Raman spectroscopy and XPS spectroscopy was used for the contact structure analysis. After thermal annealing, the metallization contains GePd phase and a thin germanium layer remains at the surface. Very slight reaction of indium with the substrate (creation of a ternary phase InGaAs) has been proved. Germanium and palladium diffuse into the GaAs substrate, the surface layer of GaAs is doped by Ge and Pd is built in the GaAs crystal structure instead of arsenic.     

聚乙烯/木粉复合材料的液相化学氧化表面处理

为提高聚乙烯/木粉复合材料的表面润湿性,采用液相化学氧化方法对聚乙烯/木粉复合材料表面进行处理,利用傅立叶变换红外光谱（FT-IR）、X射线光电子能谱（XPS）、接触角测定以及扫描电子显微镜（SEM）等分析方法研究了不同处理时间复合材料表面性质的变化。结果表明,液相化学氧化处理后,复合材料表面含氧基团增加,有大量的-O...     

Influence of synthetic parameters on the enhanced photocatalytic properties of ZnO nanoparticles for the degradation of organic dyes: a green approach

Herein, we report a green synthetic strategy using aqueous leaves extract of Actinodaphne madraspatna Bedd (AMB) for the synthesis of ZnO NPs. The physical shape, size, thermal stability, surface area, surface composition and chemical state, morphological and optical properties of the synthesized ZnO NPs are well characterized through UV–Visible diffuse reflectance spectroscopy (DRS UV), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis–differential thermal analysis (TGA–DTA), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) and X-ray photon spectroscopy (XPS). FT-IR spectrum of ZnO NPs showed a characteristic peak at 416.62 cm^?1. Optical studies of prepared ZnO NPs showed the bandgap values are reduced in the range of 3.05 to 2.96 eV. The XRD and TEM data revealed the synthesized ZnO NPs exist in wurtzite crystal structure with crystallite sizes of 18 nm to 68 nm range. The variation in bandgap, surface area and crystallite structure of ZnO NPs would be achieved by changing the experimental parameters. FESEM showed spherical-shaped structure. XPS result confirmed the atomic states of Zn and O. The green synthesized ZnO NPs were examined for the photocatalytic degradation of methylene blue (MB) and acid violet 17 (AV17) dyes under UV light and the rate constants ‘k’ was calculated. It is found that the green synthesized ZnO NPs with reduced bandgap showed enhanced photocatalytic activity with higher rate constant.

     

C and N doped nano-sized TiO2 for visible light photocatalytic degradation of aqueous pollutants

A facile large scale synthesis of high surface area anatase TiO₂ nano material has been carried out by using the solution combustion synthesis with very widely available urea as fuel. The as-obtained puffy powder of anatase TiO₂ was characterised by X-ray diffraction (XRD), Brunauer–Emmett–Teller surface area analysis, ultraviolet–visible (UV–vis) spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques in order to analyse the structural, optical and surface properties of the synthesised material. Diffuse UV–vis spectroscopic data show a red shift in absorption spectra which may be attributed to the possible energy levels added in between the band edges of TiO₂ due to the C and N doping as confirmed by XPS. Photocatalytic activity of the catalyst was assessed by the photocatalytic degradation of methyl orange under visible light irradiation. The effect of an electron acceptor in order to maximise the electron trapping for further inhibiting exciton recombination and thereby enhancing the oxidation of dyes has also been studied by using peroxomono sulphate(PMS) as the electron acceptor.     

In vivo evaluation of modified titanium implant surfaces produced using a hybrid plasma spraying processing

In this study, the biological responses to surface-modified titanium (Ti) was investigated using a dog model. Titanium plasma spraying and ion implantation of amino (NH₂⁺) groups were used as means of modifying Ti surfaces. Characterization of the modified Ti surfaces was performed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning Auger electron spectroscopy. In vivo evaluations were performed using fluorescence microscope, scanning electron microscope and energy disperse spectroscopy. It was observed in this study that ion-implanted porous-graded titanium coatings had a thick surface oxide layer, containing a small amount of nitride. In vivo study indicates direct bone contact between surface-modified Ti implants and osseous tissues. In addition, osseous tissues were observed to grow into the pores inside the coatings, thereby allowing the formation of a gradual calcium phosphate interface layer. It was concluded from this study that ion implantation of Ti surfaces with amino groups, induced higher concentration of calcium and phosphorus precipitation and more mineralization as compared to non-ion-implanted Ti surfaces.     

Characterization of the protective surface films formed on molten magnesium in air/HFC-134a atmospheres

The surface films formed on molten magnesium in an air/HFC-134a gas mixture at 700 °C were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Auger electron spectroscopy (AES). The results showed that there was a protective film on molten magnesium surface, which can prevent molten magnesium from oxidation and ignition. The surface film contained primarily four elements: magnesium, fluorine, oxygen and carbon, and was composed of MgF₂, MgO and C. The film properties depended on the HFC-134a concentration in the gaseous mixture and exposure time. The thickness of the film formed after exposure to air containing 0.5% HFC-134a for 10 min was about 1–2 μm.     

Fabrication of hierarchical structured superhydrophobic Copper surface by in-situ method with micro/nano scaled particles

Chlorofluoro silane (CFSi) decorated Copper doped SiO₂ coated Copper surface was synthesized by an in-situ method and characterized by various analytical tools like Fourier Transform Infrared (FTIR) Spectroscopy, UV-Visible spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and contact angle measurements. In the present investigation, the bulk Copper plate was served as a resource material for the generation of Copper with simultaneous chemical etching reaction in an aqueous acidic and alcoholic medium. The modified Copper surface has a contact angle of 152°.     

Co-precipitated RuO2-Al2O3 catalysts: bulk and surface characterization

A series of co-precipitated RuO₂-Al₂O₃ samples was characterized by means of bulk and surface techniques such as X-ray diffraction (XRD), specific surface area measurements, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The existence of a substitutional solid solution of Al³⁺ ions in RuO₂ is suggested on the basis of XRD results. A more detailed study of such a phase was hindered by its thermal instability. XPS and AES quantitative data indicate a strong enrichment of Al on the surface. A simple model based on a reciprocal masking action of the particles of the two oxides with respect to the primary beam (X-rays or electrons) was found to fit the surface composition data well.     

Cs/p-GaAs(100)表面的变角XPS研究

在实验数据的基础上 ,采用变角XPS分析表面层状结构的计算程序 ,应用了新算法 ,使该程序能快速可靠地计算多层多种组分的含量和层厚度。计算了Cs吸附在清洁p GaAs(1 0 0 )表面上的Cs层覆盖率及弛豫层的厚度和组分。在Cs/GaAs达到峰值光电发射时 ,Cs覆盖率为 0 71个单层 ,Ga与As弛豫层厚度为 2 3个单层 ,Ga相对As轻微富集。