Surface coverage characterization of tinplates after post‐treatment processes

In this paper, post‐treatments, including reflowing treatment, passivation treatment, and ultrasonic treatment for tinplates with different coating mass, are discussed, and surface characteristics brought by the post‐treatments have also been investigated by grazing incidence X‐ray diffraction and X‐ray photoelectron spectroscopy. Grazing incidence X‐ray diffraction results show the amount of highest iron and FeSn₂ and lowest tin on tinplate with a coating mass of 1.1 g ? m^?2, indicating the poor surface coverage of steel substrate. The amount of lowest iron and tin‐iron alloy and highest tin on tinplate with a coating mass of 11.2 g ? m^?2 indicates the best surface coverage of tinplate among the four test samples. X‐ray photoelectron spectroscopy depth analysis shows that the sample with coating mass of 1.1 g ? m^?2 has a higher amount of iron atomic concentration, which decreases sharply as the coating mass increases, indicating the poor surface coverage by lower coating mass.     

气相和溶液多硫化物钝化InP表面的XPS和AFM研究

利用X射线光电子谱和原子力显微镜研究经气相和溶液钝化的InP表面的化学健合、表面残余氧含量、表面刻蚀效应和粗糙度。结果表明 ,采用气相多硫化物钝化可以获得均匀、光滑和可重复的表面质量 ,但其热稳定性不如溶液多硫化物钝化的InP表面好     

Controlled adsorption of titanium(IV) oxide particles on electroplated zinc coatings to improve the corrosion resistance of chromium(VI)‐free conversion layers

Adsorption of nano‐scaled titanium(IV) oxide particles on electroplated zinc is performed by a simple dip‐coating technique in an aqueous titanium(IV) oxide suspension prepared with a stirred media mill. X‐ray photoelectron spectroscopy, scanning electron microscopy and X‐ray fluorescence spectroscopy are carried out to investigate the composition of the zinc surface and the thickness and porosity of the adsorbed titania films. The zinc surface formed during the electrodeposition process is of oxyhydroxide nature and the thickness of the adsorbed titania particle layer is controlled by the pH value and the solid concentration of the suspension. In the range of 10 wt.%–30 wt.% titanium(IV) oxide, a linear dependence between the titania film thickness and the solid content of titania particles in the suspension is found. Highest film thicknesses are obtained in alkaline media (pH≥9). At 13.5 wt.% titania particles and pH values below pH = 2.4, the titania particle film is not closely packed and the zinc layer underneath is still visible in electron microscopy, which is a prerequisite for imbedding these particles by a thin second zinc layer for formation of a robust chromium(VI)‐free passivation layer containing the titania particles.     

镀锡板钝化膜影响涂漆附着力的XPS分析

镀锡板钝化膜的组织结构影响后续涂漆的附着力.利用光电子能谱(XPS)分析了镀锡板钝化膜表层和内部的组织结构,从而分析其对镀锡板涂漆附着力的影响.结果表明:阴极钝化过程中钝化液夹杂杂质离子造成镀锡板钝化膜含Cl元素,Cl含量较高时涂漆附着力差;钝化膜中Cr(OH)<,3>对涂漆附着力影响较大,其含量越高,涂漆附着力越差;...     

Untersuchung dünner Schichten mittels Röntgenreflektometrie

Thin film characterization by means of X‐ray reflectometry X‐ray reflectometry and diffractometry are widely used non‐destructive methods to characterize thin films in the total thickness range which is typically between 2nm and approximately 500nm. On special arrangements a resolution up to 1000nm layer thickness has been demonstrated. Layer stack morphology, surface topography, layer structure, material density, single layer or period thickness and surface and interface roughness are the typical structural parameters both of single layers and of multilayers which can be described by the measured data. The performance of the measurement setup is mainly influenced by the parameters of the incident X‐ray beam like beam divergence, monochromatism and photon energy. In the following the influence of the optical components in the beam path to angle and energy resolution of X‐ray reflectometry is discussed.     

高硅钢用半有机绝缘涂层的制备及其性能研究

为减少高硅钢铁芯叠片间的涡流损耗,以磷酸二氢铝、苯丙乳液、甘油及水为主要原料,制备出一种适合高硅钢用无铬环保半有机绝缘涂层.利用光电子谱仪、扫描电镜及能谱仪对高硅钢脱碳退火板的氧化薄膜、绝缘涂层的微观结构形貌及部分缺陷进行分析,并研究了该涂层的涂覆量对其附着性、硬度及绝缘性能的影响.研究结果表明:普通无取向硅钢磷酸盐环保半有机绝缘涂层同样适用于高硅钢;绝缘涂层的均匀性取决于高硅钢片表面的平整度、涂辊表面质量以及对涂覆速度的平稳控制;高硅钢的表面粗糙度及氧化膜厚度对绝缘涂层的附着性有着重要影响;本试验制备的半有机涂层每面涂覆量控制在0.8~1.2 g/m2,具有良好的附着性及绝缘性能,层间电阻在5Ω·cm2/片以上.     

Cytocompatibility of novel tin oxide thin films

The capacity of tin oxide films to support cell growth was investigated. Three substrates were used for the test: glass coverslips, glass coverslips spin coated with tin oxide and commercially available 316 stainless steel. The wettabilities and surface roughness of the three surfaces were measured before seeding 3T3 fibroblasts onto the samples. The behaviour of the cells grown on the tin oxide was compared to the uncoated glass and the steel and results showed that the cell growth on tin oxide compared favourably with the other substrates. The surface wettability appeared to have the strongest effect on cell adhesion to tin oxide.     

表面预处理对钛合金表面低温等离子体氮化的影响

为提高TC4钛合金表面摩擦学性能,探究酸洗及等离子体预处理对TC4钛合金表面低温等离子体氮化进程的影响.首先采用热丝增强等离子体氮化系统分别对表面酸洗及未酸洗TC4钛合金在氩气气氛下进行等离子体预处理,然后对各种表面预处理的TC4钛合金实施低温(500℃)等离子体氮化.采用扫描电子显微镜、能谱仪及X射线衍射仪分别分析了...     

物理气相沉积黄铜镀层对钛丝绳和橡胶粘合性能的影响研究

利用物理气相沉积(PVD)在钛丝绳表面沉积黄铜镀层,研究了钛基体表面处理、黄铜镀层成分、镀层厚度以及镀层形貌对钛丝绳和橡胶粘合力的影响.结果表明,有效去除钛基体表面钝化层并采用打底过渡层方式,可以提高黄铜镀层和钛基体的结合力;钛丝绳和橡胶粘合力随着黄铜镀层中Zn含量的升高而增加,Zn≥30％时进入增长平台区;镀层厚度增...     

Influence of anode roughness and buffer layer nature on organic solar cells performance

Fluorine doped transparent conductive tin oxide thin films (FTO) of different surface roughness have been deposited by chemical vapor deposition (FTO_SOL), classical chemical spray pyrolysis (FTO_CSP), and spray pyrolysis onto heated substrates using infra red irradiation (FTO_IRSP); the three deposition methods inducing different surface roughness. It was found that the different FTOs presented similar electrical properties while their structural, morphological and optical properties were related to surface properties. These FTO films have been used as anode in multilayer organic solar cells, based on coupled donor/acceptor-copper phthalocyanine/fullerene. To improve solar cell performance, buffer layers of different natures have been tried at the anode/organic material interface. Deposition of a thin molybdenum oxide film onto FTO smooth films afforded reproducible devices with performance similar to those obtained with indium tin oxide anodes. However, cell efficiency decreased as FTO surface roughness increased. The degree of degradation depended on the nature of the buffer layer. We show that it is necessary to use buffer layer material that allows consistency and completeness of the electrode coverage.     

Oxidation behavior of AlN substrate at low temperature

The oxidation onset and the kinetics of polycrystalline AlN substrates were studied by measuring the weight percent of oxygen in the surface layer and the surface roughness with energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM), respectively. The oxidation started in the temperature range 800–900 °C and the entire surface of the AlN substrate was covered with an Al₂O₃ oxide layer below 1100 °C. The oxidation kinetics followed a linear rate law below 1000 °C and a parabolic rate law above 1100 °C. Above 1100 °C, the surface roughness increased abruptly by the irregular shape of overgrown oxide, which might enhance the adhesion of metal to the AlN surface in a metallization process. With an increase of the oxidation temperature above 1200 °C, the oxide layer split during cooling due to the thermal expansion mismatch between the AlN matrix and the Al₂O₃ oxide layer.     

Fatigue of additively manufactured 316L stainless steel: The influence of porosity and surface roughness

The fatigue behaviour of additively manufactured (AM) 316L stainless steel is investigated with the main emphasis on internal porosity and surface roughness. A transition between two cases of failure are found: failure from defects in the surface region and failure from the internal defects. At low applied load level (and consequently a high number of cycles to failure), fatigue is initiating from defects in the surface region, while for high load levels, fatigue is initiating from internal defects. Porosities captured by X‐ray computed tomography (XCT) are compared with the defects initiating fatigue cracks, obtained from fractography. The fatigue data are synthesised using stress intensity factor (SIF) of the internal and surface defects on the fracture surface.     

氧等离子体处理对氧化铟锡表面化学状态影响的ADXPS研究

利用变角X射线光电子谱对氧等离子体处理前后氧化铟锡ITO薄膜的表面化学状态进行了表征.实验发现用溶剂清洗之后的ITO薄膜表面存在一层厚度大约为0.7nm的非导电碳氢化合物污染层.氧等离子体处理方法可有效地消除C污染,而残存的少量污染C被部分氧化形成含羰基和羧基的化学物种.氧等离子体处理不仅提高了约5.0nm深度范围内的ITO薄膜表层中O的总体含量,更重要的是提高了膜层中O2-离子氧种的含量,改变了膜层化学结构,使得ITO薄膜表面的导电性能降低,同时改善了整个表面层化学结构的均匀性.     

Microstructure behaviour and influence on thermally grown oxide formation of double‐ceramic‐layer EB‐PVD thermal barrier coatings annealed at 1,300 °C under ambient isothermal conditions

To resist high thermal loads in turbines effectively, turbine blades are protected by thermal barrier coatings in combination with additional air cooling. State‐of‐the‐art yttria stabilised zirconia top coats do not operate at temperatures higher than 1,200 °C. Promising candidates for alternative top coats are pyrochlores, lanthanum zirconate and gadolinium zirconate. But lifetime of pyrochlores is short because of spallation. However, combinations of yttria stabilised zirconia and lanthanum zirconate or gadolinium zirconate as multilayer systems are promising top layers operating at higher temperatures than yttria stabilised zirconia. Such thermal barrier coatings top coats as double‐ceramic‐layer systems consisting of 7 wt.% yttria stabilised zirconia and lanthanum zirconate or gadolinium zirconate were deposited by Electron Beam‐Physical Vapour Deposition. The focus of the work was set on the influence of the coating design and the microstructure variation generated at different rotating speeds on the adhesion and thermally grown oxide behaviour after isothermal oxidation at 1,300 °C. Phase formation of the thermal barrier coatings top coats was obtained using X‐ray diffraction. After isothermal oxidation tests for 50 h at 1,300 °C, both, microstructure change and the formation of the thermally grown oxide were investigated. While the pyrochlore single‐ceramic‐layer are completely spalled off, microstructure of the double‐ceramic‐layer reveals only crack initiation. The thermally grown oxide thickness was determined by means of scanning electron microscopy. A high aluminum and oxygen content in the thermally grown oxide is found using X‐ray spectroscopy. Existence of α‐phase in Al₂O₃ was proved by X‐ray diffraction. After isothermal testing, no phase transformation can be detected regarding the double‐ceramic‐layer coatings.     

Sulfur passivation and contact methods for GaAs nanowire solar cells

The effect of sulfur passivation on core-shell p-n junction GaAs nanowire (NW) solar cells has been investigated. Devices of two types were investigated, consisting of indium tin oxide contact dots or opaque Au finger electrodes. Lateral carrier transport from the NWs to the contact fingers was achieved via a p-doped GaAs surface conduction layer. NWs between the opaque contact fingers had sidewall surfaces exposed for passivation by sulfur. The relative cell efficiency increased by 19% upon passivation. The contribution of the thin film grown between the NWs to the total cell efficiency was estimated by removing the NWs using a sonication procedure. Mechanisms of carrier transport and photovoltaic effects are discussed on the basis of spatially resolved laser scanning measurements.     

Effects of different kinds of seed layers and heat treatment on adhesion characteristics of Cu/(Cr or Ni–Cr)/PI interfaces in flexible printed circuits

In this study, the effect of various seed layers (95Ni–5Cr, 80Ni–20Cr and Cr) on the adhesion strength of flexible copper clad laminate (FCCL), which was manufactured by the roll-to-roll process, was evaluated after heat treatment. The changes in the morphology, chemical bonding, and adhesion properties were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and a 90° peel test. The results showed that both the peel strength and thermal resistance of the FCCL increased as the Cr ratio of the seed layer increased. The roughness of the fracture surface decreased as the heat treatment temperature and holding time increased. The heat treatment of the FCCL increased the proportion of C–N bonds and reduced that of the C–O and carbonyl (C=O) bonds in the polyimide. The chemical function and roughness of the fracture surface were affected by the composition and ratio of the seed layer. Therefore, the adhesion strength between the metal and polyimide was mostly attributed to the chemical interaction between the metal layer and the functional groups of the polyimide.     

Controlling the Growth Kinetics and Optoelectronic Properties of 2D/3D Lead–Tin Perovskite Heterojunctions

Halide perovskites are emerging as valid alternatives to conventional photovoltaic active materials owing to their low cost and high device performances. This material family also shows exceptional tunability of properties by varying chemical components, crystal structure, and dimensionality, providing a unique set of building blocks for new structures. Here, highly stable self‐assembled lead–tin perovskite heterostructures formed between low‐bandgap 3D and higher‐bandgap 2D components are demonstrated. A combination of surface‐sensitive X‐ray diffraction, spatially resolved photoluminescence, and electron microscopy measurements is used to reveal that microstructural heterojunctions form between high‐bandgap 2D surface crystallites and lower‐bandgap 3D domains. Furthermore, in situ X‐ray diffraction measurements are used during film formation to show that an ammonium thiocyanate additive delays formation of the 3D component and thus provides a tunable lever to substantially increase the fraction of 2D surface crystallites. These novel heterostructures will find use in bottom cells for stable tandem photovoltaics with a surface 2D layer passivating the 3D material, or in energy‐transfer devices requiring controlled energy flow from localized surface crystallites to the bulk.     

EPMA‐Analyse dünner PVD‐ und CVD‐Schichten

EPMA analysis of thin PVD and CVD layers Electron Probe Micro Analysis (EPMA) is an X‐ray spectroscopic method for determining the chemical composition of solid substances in the near‐surface region. It has a high detection sensitivity, a high spatial resolution, an adjustable depth of analysis and is easy and accurate to quantify. Less well known is the fact that the EPMA is also able to analyze the chemical composition and layer thicknesses of thin multi‐layer systems non‐destructively and with only one single measurement. In particular, it is possible to determine, for example, the composition and thickness of a layer buried under one or more other layers. Conversely, with a known film thickness, the density of thin layers can be determined, a quantity that is generally difficult to access with thin layers. The following article describes the physical basics of EPMA analysis and compares them with energy dispersive X‐ray spectroscopy (EDX) and X‐ray fluorescence analysis (XRF), which are also widely used. The principle of so‐called thin film analysis for multilayer systems is explained, and the possibilities and limitations of this method are illustrated by a number of industrial application examples.     

Microfluidics: Nanostructuring of Titania Thin Films by a Combination of Microfluidics and Block‐Copolymer‐Based Sol–Gel Templating (Small 7/2011)

Sol–gel templating of titania thin films with the amphiphilic diblock copolymer poly(dimethyl siloxane)‐block‐methyl methacrylate poly(ethylene oxide) is combined with microfluidic technology to control the structure formation. Due to the laminar flow conditions in the microfluidic cell, a better control of the local composition of the reactive fluid is achieved. The resulting titania films exhibit mesopores and macropores, as determined with scanning electron microscopy, X‐ray reflectivity, and grazing incidence small angle X‐ray scattering. The titania morphology has three features that are beneficial for application in photovoltaics: 1) a large surface‐to‐volume ratio important for charge generation with disordered hexagonally arranged mesopores of 25 nm size and a film porosity of up to 0.79, 2) enhanced light scattering that enables the absorption of more light, and 3) a dense titania layer with a thickness of about 6 nm at the substrate (bottom electrode) to prevent short circuits. An optical characterization complements the structural investigation.     

Surface Modification of Electrospun Polycaprolactone Nanofiber Meshes by Plasma Treatment to Enhance Biological Performance

A critical aspect in the development of biomaterials is the optimization of their surface properties to achieve an adequate cell response. In the present work, electrospun polycaprolactone nanofiber meshes (NFMs) are treated by radio‐frequency (RF) plasma using different gases (Ar or O₂), power (20 or 30 W), and exposure time (5 or 10 min). Morphological and roughness analysis show topographical changes on the plasma‐treated NFMs. X‐ray photoelectron spectroscopy (XPS) results indicate an increment of the oxygen‐containing groups, mainly ? OH and ? C?O, at the plasma‐treated surfaces. Accordingly, the glycerol contact angle results demonstrate a decrease in the hydrophobicity of plasma‐treated meshes, particularly in the O₂‐treated ones. Three model cell lines (fibroblasts, chondrocytes, and osteoblasts) are used to study the effect of plasma treatments over the morphology, cell adhesion, and proliferation. A plasma treatment with O₂ and one with Ar are found to be the most successful for all the studied cell types. The influence of hydrophilicity and roughness of those NFMs on their biological performance is discussed. Despite the often claimed morphological similarity of NFMs to natural extracellular matrixes, their surface properties contribute substantially to the cellular performance and therefore those should be optimized.