Perchlorate interchange during the redox process of PPy/PVS films in an acetonitrile medium. a voltammetric and EDX study

Polypyrrole/poly(vinyl sulfonate) (PPy/PVS) films in acetonitrile containing 0.1 M LiClO4 were studied by cyclic voltammetry. Consecutive voltammograms pointed to a continuous increase in the charge involved in the process, suggesting a rise in the number of the electroactive participants involved in the redox process. However, voltammograms obtained for the PPy/ClO4 films in analogous conditions pointed to a steady-state behavior from the very early cycles. Theoretical studies based on the Nernst and Butler-Volmer equations indicated that perchlorate ions are involved during the oxidation/reduction process of the PPy/PVS films when the steady state is reached. This result was confirmed by "ex situ" energy-dispersive X-ray analysis of the films. In this regard, the electrochemical behavior of PPy/PVS polymers was similar to that of PPy/ClO4 films when a high number of cycles were carried out. The exchange of ClO4- during the redox reaction of the PPy/PVS films made it necessary to incorporate Li+ cations inside the polymer during the initial voltammetric cycles to compensate for the negative charges of PVS polyanions. Li+ cations are mainly stabilized inside the polymer by the ion pairs formed with the sulfonated groups of the PVS. An increase and shift of the voltammetric cycles indicated a restructuring of the polymeric chains with consecutive scans.     

RFA as control method of the reactive sputtering process of TiN films

In-situ X-ray fluorescence (XRF) analysis has been used to control the deposition process of Ti-N films on steel substrates during reactive sputtering. The analysis system consisted of a tungsten X-ray tube, secondary targets of Cu, Fe and Cr and a Si (Li) detector. The sputtering off the Ti target has been determined indirectly by plasma monitoring using optical emissions spetroscopy (OES) of the Ti atoms, and the film growth has been measured directly by XRF analysis of the surface mass of Ti atoms deposited on the substrate. For zero bias voltage and varying N₂ flow the increment of surface mass per deposition time has been found to incrase linearly with the intensity of the OES signal of Ti. A negative bias voltage U_B100 V changes strongly the growth rate by resputtering effects, especially in the range where stoichiometric TiN is formed.     

Analysis of Ti-N films by calibration of Ti X-ray spectra

Summary An energy-dispersive X-ray analysis of Ti_1–xN_x films was performed by using an Si(Li) detector. The Ti_1–xN_x films were sputtered on polished steel substrates in a mixed Ar+N₂ atmosphere by a reactive magnetron sputtering technique. Because the nitrogen X-ray line is absorbed by the Be window, an analysis method was developed based solely on the calibration of the characteristic Ti-K-intensities using a high-purity Ti standard. The film compositions were computed by means of a ZAF procedure. The samples closest to stoichiometric composition show maximum hardness.     

EDX depths analysis of MIS-structures

Based on experimental energy transfer distributionsdE/dx including the X-ray depth distribution function (x,E ₀,Z) an effective-layer method has been developed in order to homogenize a multilayer target. Effective layer thicknesses are related to real layer thicknesses by means of equal transmission-energy rates. This method has been proved by EDX measurements of Au-SiO₂-Si structures showing good agreement with the real structures.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

Comparative composition analysis of SiOx and SiNx thin films by AES,EDX and RBS

The chemical composition of thin films in SiO_x and SiN_x systems (“SIPOS”) have been analyzed by comparative AES, EDX, and RBS of the same samples to assess the extent of possible errors introduced by the “weak points” of each method. These exist for EDX in the necessity of a thickness correction, for AES in a possible composition dependence of the sensitivity factors, and for RBS in the low sensitivity in detecting light elements. Linear correlations between the data obtained by RBS and EDX have been revealed over the whole range of x. Therefore, EDX can be calibrated by appropriate standards of pure SiO₂ or Si₃N₄ films. For AES analysis a calibration curve is needed. Using RBS data for calibration the content of the light components O and N might be slightly overestimated by this method.     

Investigation of the formation process of MCs+-molecular ions during sputtering

In secondary ion mass spectrometry, the detection of MCs+ clusters (with M an element of the specimen) under a Cs bombardment is frequently used for the quantification of major elements. Despite some very good results obtained by this method, some problems still remain. In order to gain some more insight into these problems, the formation mechanism of the MCs+ clusters is investigated using a Monte Carlo model. It is shown that the majority of the constituent particles of the formed clusters are initially first or second neighbor atoms at the surface and that the velocity distribution of the MCs+ clusters becomes broader and peaked at higher velocities with increasing surface binding energy of the M atom. In addition, it is demonstrated that the interaction potential between the M and Cs+ particle has no influence on the velocity distribution of the MCs+ clusters. On the other hand, the cluster formation probability, defined as the probability that a sputtered M and Cs+ particle will form a MCs+ cluster, is extremely sensitive to this interaction potential. It is also shown that the cluster formation probability decreases with increasing surface binding energy. Finally, a good correspondence is obtained between the calculated and experimental velocity distributions of MCs+ clusters sputtered from different monoatomic materials. As a consequence, the Monte Carlo model and the discussed results can be validated.     

The effect of glow discharge sputtering on the analysis of metal oxide films

The potential of radiofrequency glow discharge optical emission spectrometry (rf-GD-OES) for the quantification and the solid-state speciation of metal oxide films has been investigated in this work. Two types of oxide coatings, an iron oxide film deposited on silicon and a chromate conversion coating (CCC), were studied at 700 Pa of pressure and 30 W of forward power. The metal to oxygen ratios in the quantitative depth profiles (Fe/O and Cr/O, respectively) were used to evaluate the oxidation states of iron and chromium in the oxide films, demonstrating the capability of GD-OES technique for depth-resolved solid-state speciation. Furthermore, the effect of glow discharge sputtering on the samples surface in terms of modifications in the surface morphology and species transformations, were investigated by using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The iron and chromium oxidation states were carefully studied by XPS at the original samples surface and at the bottom of GD craters, and a systematic reduction of metal elements was observed after rf-GD-OES analysis. In the case of thin oxide films, preferential sputtering can be considered as a critical factor since oxygen atoms can be preferentially sputtered, leaving a metal-enriched surface and, therefore, promoting the reduction of metal elements. In the present study preferential sputtering was found to be sample dependent, changing the proportion of the metal reduction in the oxide film with its composition. Additionally, alternative sputter-depth-profiling techniques such as secondary ion mass spectrometry (SIMS), femtosecond laser ablation (fs-LA), and XPS ion gun were used for the analysis of the CCC in order to evaluate the reduction of Cr⁶⁺ to Cr³⁺ depending on the sputtering mechanism.     

Structural study of oriental lacquer films during the hardening process

Oriental lacquer is the natural resin obtained by tapping lac trees. It hardens into a tough and insoluble film. The extreme hardness and insolubility are some of the most important functions, which are required for industrial coating materials. In this study, two kinds of oriental lacquer films, traditionally named Kiurushi (raw urushi) and Kuromeurushi produced by two different pretreatments, were analyzed during hardening with Fourier transform infrared spectroscopy (FT-IR), thermogravimetry/differential thermal analysis-mass spectrometry (TG/DTA-MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to investigate their functional expression process. Typical functional groups of the lacquer films were detected by FT-IR. The TG/DTA-MS curves clarified that the thermal degradation of the lacquer films gradually began at around 200 °C, and reached the fastest rate at 400-500 °C. Apparently, FT-IR and TG/DTA-MS could not reveal any difference between the films. On the other hand, Py-GC/MS revealed differences between the films in the peak area ratios of 3-pentadecenylcatechol to 3-pentadecylcatechol and 3-pentadecadienylcatechol to 3-pentadecylcatechol. The ratios of Kiurushi lacquer film were higher than those of Kuromeurushi lacquer film. Both ratios, furthermore, decreased during hardening due to polymerization of the alkenylcatechols into an urushiol polymer skeleton comprising nucleus-side chain and side chain-side chain cross-linkages with 3-pentadecylcatechol at the terminal. The present results suggest that the reaction rate of these cross-linkages in Kuromeurushi lacquer film is faster than that in Kiurushi lacquer film. A good correlation was found between the peak area ratios obtained by Py-GC/MS and hardness obtained by pencil hardening testing. Oriental lacquer expresses the functions - an extreme hardness and insolubility - accelerating the nucleus-side chain and side chain-side chain cross-linkages. Furthermore, it has become clear that the traditional treatments called Nayashi and Kurome effectively accelerate the hardening rate by activating the cross-linkages.     

Analytical study by SEM/EDX and metallographic techniques of materials used in the iron production process during the iberian period

This work is the archaeometric study of different types of materials used in iron production in the Iberian Period (6th-2nd century b.c.). The materials were recovered in several archaeological digs (which makes it possible to date the archaeological remains) on different sites in the Levante area of the Iberian Peninsula. The samples selected for this study belong to different materials used in the ancient iron production process such as ores, slags, finished objects, etc. The use of scanning electron microscopy (SEM) is proposed to observe surface images of the samples to determine their morphological, microstructural and topographic characteristics to obtain valuable information on the materials studied. The study also proposes chemical analysis of the elements in the sample by X-ray microanalysis (SEM/EDX) which provides both qualitative and quantitative information. The archaeometric study suggests that the iron obtained was very good quality, but the process was not economically efficient when viewed from today's perspective. Furthermore, the slag produced in the furnace can be related with the slag or impurities contained in the iron. It has also been possible to relate the ores and slag, some furnace conditions, the use of fluxes and also to differentiate types of slag.     

Comparative composition analysis of SiOx and SiNx thin films by AES, EDX and RBS

The chemical composition of thin films in SiO_x and SiN_x systems (SIPOS) have been analyzed by comparative AES, EDX, and RBS of the same samples to assess the extent of possible errors introduced by the weak points of each method. These exist for EDX in the necessity of a thickness correction, for AES in a possible composition dependence of the sensitivity factors, and for RBS in the low sensitivity in detecting light elements. Linear correlations between the data obtained by RBS and EDX have been revealed over the whole range of x. Therefore, EDX can be calibrated by appropriate standards of pure SiO₂ or Si₃N₄ films. For AES analysis a calibration curve is needed. Using RBS data for calibration the content of the light components O and N might be slightly overestimated by this method.     

GC/MS analysis of gaseous degradation products formed during extrusion blow molding process of PE films

Results of the investigation of volatile organic compounds emission during polyethylene extrusion are presented. Two polymers of different processing properties were tested, namely linear low density polyethylene (ExxonMobil) and high density polyethylene (Liten FB 29). Blowing film extrusion in experimental technological line using a single screw extruder as the imported element was done. VOCs were collected on sorbent tubes containing Tenax. Gas chromatography coupled with mass spectrometry (GC/MS) was applied for the identification of volatile degradation products. PE LLD material emits a significantly larger amount of hydrocarbons than PE-HD. Its emission contains mainly C18 and C20 hydrocarbons (alkanes, 1-alkenes, and α,ω-alkadienes). In case of the PE-HD polymer, lower degradation was observed and C18 and C23 hydrocarbons were emitted.     

Monitoring the polymerization process of polypyrrole films by thermogravimetric and X-ray analysis

Bio-composite fibers were developed from wood pulp and polypropylene (PP) by an extrusion process. The thermo-physical and mechanical properties of wood pulp-PP composite fibers, neat PP and wood pulp were studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The thermal stability of bio-composite fibers was found to be significantly higher than pure wood pulp. An understanding into the melting behaviour of the composite system was obtained which would assist in selecting a suitable temperature profile for the extruder during processing. The visco-elastic properties of bio-composite fibers were also revealed from the study. The generated bio-composite fibers were also characterized using Fourier transform infrared spectroscopy (FTIR) to understand the nature of chemical interaction between wood pulp reinforcement and PP matrix. The use of maleated polypropylene (MAPP) as a compatibilizer was investigated in relation to the fiber microstructure. Changes in absorption peaks were observed in FTIR spectra of bio-composite fibers as compared to the pure wood pulp which indicated possible chemical linkages between the fiber and polymer matrix.     

Preparation of films from aluminum acetylacetonate by plasma sputtering

Aluminum acetylacetonate has been reported as a precursor for the deposition of alumina films using different approaches. In this work, alumina‐containing films were prepared by plasma sputtering this compound, spread directly on the powered lowermost electrode of a reactor, while grounding the substrates mounted on the topmost electrode. Radiofrequency power (13.56 MHz) was used to excite the plasma from argon atmosphere at a working pressure of 11 Pa. The effect of the plasma excitation power on the properties of the resulting films was studied. Film thickness and hardness were measured by profilometry and nanoindentation, respectively. The molecular structure and chemical composition of the layers were analyzed by Fourier transform infrared spectroscopy and energy dispersive spectroscopy. Surface micrographs, obtained by scanning electron microscopy, allowed the determination of the sample morphology. Grazing incidence X‐ray diffraction was employed to determine the structure of the films. Amorphous organic layers were deposited with thicknesses of up to 7 µm and hardness of around 1.0 GPa. The films were composed by aluminum, carbon, oxygen and hydrogen, their proportions being strongly dependent on the power used to excite the plasma. A uniform surface was obtained for low‐power depositions, but particulates and cracks appeared in the high‐power prepared materials. The presence of different proportions of aluminum oxide in the coatings is ascribed to the different activations promoted in the metalorganic molecule once in the plasma phase. Copyright © 2013 John Wiley & Sons, Ltd.     

Properties of ITO films prepared by reactive magnetron sputtering

Indium tin oxide (ITO) thin films were deposited by mid frequency pulsed dual magnetron sputtering using a metallic alloy target with 10 wt.% tin in an atmosphere of argon and oxygen. The aim of the work was to study the interdependence of structural, electrical and optical properties of ITO films deposited in the reactive and transition target mode, respectively. The deposition rate in the transition mode exceeds the deposition rate in the reactive mode by a factor of six, a maximum value of 100 nm·m min⁻¹ could be achieved. This corresponds to a static deposition rate of 200 nm min⁻¹. The lowest electrical resistivity of 1.1·10⁻³ Ω cm was measured at samples deposited in the high oxygen flow range in the transition mode. The samples show a good transparency in the visible range corresponding to extinction coefficients being below 10⁻². X-ray diffraction was used to characterise crystalline structure as well as film stress. ITO films prepared in the transition mode show a slightly preferred orientation in (211) direction, whereas films deposited in the reactive mode are strongly (222) oriented. Compared to undoped In₂O₃ all samples have an enlarged lattice. The lattice strain perpendicular to the surface is about 0.8% and 2.0% for films grown in the transition and the reactive mode, respectively. Deposition in the transition mode introduces a biaxial film stress in the range of −300 MPa, while stress in reactive mode samples is −1500 MPa.     

航天器管路吹除污染物成分分析与来源解析

制定了航天器管路吹除污染物检测总体技术方案,并依据方案分别采用扫描电镜能谱检测技术、衰减全反射傅立叶红外光谱检测技术和液相色谱-质谱联用检测技术,对航天器产品在管路吹除过程中发现的黄色污染物液体进行了成分分析,结果表明,航天器管路吹除污染物的主要成分为苯酚类物质和油脂类物质,污染物来源于航天器生产加工工艺过程中使用的润...     

Characterization of the stoichiometry of coevaporated FeSix films by AES, EDX, RBS, and electron microscopy

The composition of FeSi_x films on Si coevaporated from separate sources of Fe and Si was analyzed comparatively by AES, EDX, RBS, and electron microscopy. Cross-checks between EDX and RBS reveal systematic errors originating from the spectra background subtraction in RBS and from the thickness correction of the EDX signals. PCA (principal component analysis) assisted AES was successfully applied to the characterization of different Si bonding states in nonstoichiometric FeSi_x films. For the growth of β-FeSi₂ films by means of molecular beam epitaxy (MBE) the adjustment of the atomic beam intensities is reported in order to illustrate the capabilities of the various techniques.     

PMN-PT thin films grown by sputtering on silicon substrate: influence of the annealing temperature on the physico-chemical and electrical properties of the films

Studies of piezoelectric and electrostrictive properties of (1?x)PMN-xPT thin films were carried out. We have chosen the compositions 90/10 and 70/30, which exhibit, respectively, mostly electrostrictive and piezoelectric behaviour in bulk material. Annealing temperature effects on PMN-PT structural, dielectric, ferroelectric and electromechanical properties have been investigated. We demonstrate that with conventional annealing the pure perovskite phase can be obtained at very low temperature (400°C) without any pyrochlore phase for the two compositions. We show that electromechanical response is a mix between electrostrictive and piezoelectric response for the two compositions. However, as can be easily understood, piezoelectric contribution is larger for 70/30. It is shown that electrical responses of the films obtained at 400°C are largely satisfied for many applications; for higher annealing temperature we observe an enhance of the electrical properties due to an improvement of the material quality in terms of crystalline structure.     

Metallized polyimide films: Metallization and mechanism of the process

The formation of metallized polyimide films in situ, namely, the alkaline hydrolysis of film surfaces, chelation of the modified surface with metal ions, and their chemical reduction giving rise to a metal layer, has been investigated. Initial polyimide films are cast from reaction solutions on a glass substrate. The solutions are prepared through the polycondensation of dianhydride of tricyclo[4.2.2.0^2.5dec-7-ene-3,4,9,10-tetracarboxylic acid and 4,4¹-diaminodiphenyl oxide in N-methyl-2-pyrrolidone at 160°C. It has been shown that alkaline water-alcohol solutions are optimal media for the hydrolysis of the film surface. The maximal exchange of alkali metal ions is achieved through formation of a more stable metal-ligand complex of poly(amido acid), with the chelation rate depending on the nature of a metal. The metal reduction proceeds rapidly; however, the mechanism of this process depends on the pH of a medium. The annealing of metallized films results in the imidization of poly(amido acid) and in the growth of metal grains on the material surface to yield a metal layer with good optical properties and high conductivity.     

Magnetic characteristics of nanocrystalline GaMnN films deposited by reactive sputtering

The magnetic characteristics of Ga_1−xMn_xN nanocrystalline films (x = 0.08 and x = 0.18), grown by reactive sputtering onto amorphous silica substrates (a-SiO₂), are shown. Further than the dominant paramagnetic-like behaviour, both field- and temperature-dependent magnetization curves presented some particular features indicating the presence of secondary magnetic phases. A simple and qualitative analysis based on the Brillouin function assisted the interpretation of these secondary magnetic contributions, which were tentatively attributed to antiferromagnetic and ferromagnetic phases.