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1.
The siliconization of pharmaceutical glass containers is an industrially frequently applied procedure. It is done by spreading an aqueous silicone oil emulsion film on the inner surface and successive heat curing treatment at temperatures above 300?°C for 10–30 min. It was often proposed that a covalent bonding of PDMS to the glass or branching of the linear PDMS occurs during heat treatment. The present study was performed for a detailed investigation of the glass and silicone (polydimethylsiloxane = PDMS) chemical state before and after heat-curing treatment and analysis of the bond nature. Combined X–ray excited photoelectron (XPS) and Auger electron spectroscopy as well as angle resolved XPS-measurements were used for analysis of the glass samples. The silicon surface atoms of the borosilicate container glass were transformed to a quartz-like compound whereas the former linear PDMS had a branched, two-dimensional structure after the heat curing treatment. It was concluded that the branching indicates the formation of new siloxane bonds to the glass surface via hydroxyl groups. Further evidence for the presence of bonded PDMS at the glass surface can be found in the valence band spectra of the siliconized and untreated samples. However, this bond could not be detected directly due to its very similar nature to the siloxane bonds of the glass matrix and the organosilicon backbone of PDMS. Due to the high variation of data from the siliconized samples it was concluded, that the silicone film is not homogeneous. Previously raised theories of reactions during heat-curing glass siliconization are supported by the XPS data of this investigation. Yet, the postulation of fixing or baking the silicone on the glass surface is only partially true since the bonded layer is very thin and most of the silicone originally on the surface after heat curing can be removed by suitable solvents. This fraction can therefore still interact with drug products being in contact to the siliconized container wall. 相似文献
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《Surface and interface analysis : SIA》2003,35(5):445-449
Surface states of polydimethylsiloxane (PDMS) treated by plasma were investigated by x‐ray photoelectron spectroscopy and surface voltage decay. X‐ray photoelectron spectroscopy confirmed the formation of a silica‐like (SiOx, x = 3–4) oxidative surface layer. This layer increased in thickness with increasing exposure duration of plasma. Plasma exposure lowers the surface resistivity from 1.78 × 1014 to 1.09 × 1013 Ω □?1 with increasing plasma treatment time. By measuring the decay time constant of surface voltage, the calculated surface resistivity was compared with the value measured directly by a voltage–current method; good agreement between the two methods was obtained. It was observed that plasma treatment led to a decrease in the thermal activation energy of the surface conduction from 31.0 kJ mol?1 for an untreated specimen to 21.8 kJ mol?1 for a plasma‐treated specimen for 1 h. Our results allow the examination of effects of plasma on the electrical properties of PDMS. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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A method is discussed for obtaining narrow Auger electron lines of atoms, molecules and solids with a halfwidth much smaller than the natural width Γn of a respective intermediate X-ray excited state |n>. The method provides a possibility of resolving diverse fine structures in Auger spectra. 相似文献
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Bolognesi P Coreno M Avaldi L Storchi L Tarantelli F 《The Journal of chemical physics》2006,125(5):054306
The N 1s Auger spectra for the two nonequivalent N atoms in N2O have been measured via Auger electron-photoelectron coincidence spectroscopy. The site-selected Auger spectra are compared with the normal Auger spectrum and with accurate theoretical calculations accounting for the effects of the dynamics of the nuclei on the energy and linewidth of the Auger bands. Such effects are found to be crucial factors in determining the different band shapes in the site-selected spectra. 相似文献
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I. Hjelte M. N. Piancastelli C. M. Jansson K. Wiesner O. Bjrneholm M. Bssler S. L. Sorensen S. Svensson 《Chemical physics letters》2003,370(5-6):781-788
We present evidence for ultra-fast dissociation of molecular ammonia when photo-excited to the N1s→4a1 core-hole state. This finding is based on resonant Auger spectroscopical results as well as qualitative arguments concerning the photon energy dependence of the Auger structures. Calculations of the excited state potential based on the Z+1 approximation were performed. Both the calculations and the measurements indicate that the most likely fragmentation pathway for the core excited ammonia molecules leads to NH2* and H fragments. 相似文献
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Combined high-resolution AES and EDX studies have been performed of a number of industrial phosphate conversion layers on steel in order to determine the importance of the surface composition for the corrosion protection of the phosphated steel.
The well-known Cr(III) rinse of zinc-iron phosphate which improves its long-term paint adhesion performance was found to result in an exchange of Zn2+ with Cr3+ ions in the surface layers of the crystals. Corrosion improvement is caused by a slower rate of attack of the Cr-containing crystals due to the low solubility of CrP04 in aqueous media.
A commercial calcium-zinc-iron phosphate system was studied for corrosion resistance in relation to its conditions of formation. Phosphate layers with optimum corrosion resistance were found to have a strongly enriched iron content in the surface layers. 相似文献
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Ohrwall G Fink RF Tchaplyguine M Ojamäe L Lundwall M Marinho RR Naves de Brito A Sorensen SL Gisselbrecht M Feifel R Rander T Lindblad A Schulz J Saethre LJ Mårtensson N Svensson S Björneholm O 《The Journal of chemical physics》2005,123(5):054310
(H2O)(N) clusters generated in a supersonic expansion source with N approximately 1000 were core ionized by synchrotron radiation, giving rise to core-level photoelectron and Auger electron spectra (AES), free from charging effects. The AES is interpreted as being intermediate between the molecular and solid water spectra showing broadened bands as well as a significant shoulder at high kinetic energy. Qualitative considerations as well as ab initio calculations explain this shoulder to be due to delocalized final states in which the two valence holes are mostly located at different water molecules. The ab initio calculations show that valence hole configurations with both valence holes at the core-ionized water molecule are admixed to these final states and give rise to their intensity in the AES. Density-functional investigations of model systems for the doubly ionized final states--the water dimer and a 20-molecule water cluster--were performed to analyze the localization of the two valence holes in the electronic ground states. Whereas these holes are preferentially located at the same water molecule in the dimer, they are delocalized in the cluster showing a preference of the holes for surface molecules. The calculated double-ionization potential of the cluster (22.1 eV) is in reasonable agreement with the low-energy limit of the delocalized hole shoulder in the AES. 相似文献
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A corrosion-resistant complex film formed in ethylenediaminetetra(methylidenephosphonic acid) (EDTMP) solution was determined by x-ray photoelectron spectroscopy and Auger electron spectroscopy to consist of 48.0% O, 11.7% Sn, 7.7% N, 22.1% C and 10.5% P. From the differences in the binding energies of Sn, N and O before and after film formation and the RPO2?3 and SnN vibrations in the Raman spectrum of the film, it was deduced that N and O in EDTMP were coordinated with Sn in the film. 相似文献
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Baunack S Plotnikov A Wrobel R Vogt C Wetzig K 《Analytical and bioanalytical chemistry》2002,374(4):681-684
The suitability of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for precise analysis of YNi(2)B(2)C has been investigated. The intensity ratios B/Y and Ni/Y were found to vary during ablation as a function of the ablation conditions. This could be because of fractionation, owing to incongruent ablation or transport and plasma effects. The bottoms and surroundings of the craters were investigated by scanning Auger electron spectrometry. The bottoms of the craters produced by ablation are covered with a thin oxide comparable with that on the polished crystal surface.The craters are surrounded by an oxide layer the dimensions and thickness of which depend on the laser conditions. The formation of this oxide can be assumed to be a result of partial oxidation of sample material during the ablation process; the oxide is then redeposited around the laser crater. 相似文献
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《Surface and interface analysis : SIA》2003,35(10):773-778
Silicon carbide powder samples were heated at temperatures between 600 °C and 850 °C in wet and dry air to investigate the effect of moisture on the oxidation kinetics. Equations were derived to calculate the surface oxide thickness from both the Si 2p XPS spectra and from the Si KLL bremsstrahlung‐excited Auger spectra. The oxide film growth rates are shown to be parabolic. The film thickness formed during oxidation in wet air was larger than that in dry air for the same temperature and heating time. The activation energy for wet oxidation was found to be significantly lower than that for dry oxidation within this temperature range. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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Thomas Wirth 《Fresenius' Journal of Analytical Chemistry》1993,346(1-3):308-309
Summary Quantitative AES analysis has been carried out on PtSi and Pd2Si using dN(E)/dE spectra. The concentration ratios are determined by elemental sensitivity factors after correcting for matrix and sputter effects. In the case of matrix correction an improved correction procedure has been developed which considers effects created by different atomic densities, electron backscattering, electron attenuation and peak shapes. The concentration ratios Xmetal/XSi deduced from measurements of mechanically cleaned sample surfaces agree very well with the nominal bulk values of the silicides. Ion bombardment creates strong intensity and line shape changes of the Auger signals. Therefore, in case of sputtered silicide surfaces, both matrix and sputter effects must be corrected. 相似文献
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Bauer HE 《Analytical and bioanalytical chemistry》1995,353(3-4):450-455
A purely formal method for background removal in electron beam induced Auger electron spectroscopy is presented. The method has been developed for practical purposes. It is typically used to remove the background of a complete recorded spectrum, no fit is necessary to remove the backscattered electrons background. An overcompensation of the background, resulting in negative values of the background removed spectrum is not possible, all values of the background removed spectrum are positive or zero. Since the Auger peaks are separated by zeros after background removal, the method is well suited for peak finding and identification. 相似文献
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H. E. Bauer 《Fresenius' Journal of Analytical Chemistry》1995,353(3-4):450-455
A purely formal method for background removal in electron beam induced Auger electron spectroscopy is presented. The method has been developed for practical purposes. It is typically used to remove the background of a complete recorded spectrum, no fit is necessary to remove the backscattered electrons background. An overcompensation of the background, resulting in negative values of the background removed spectrum is not possible, all values of the background removed spectrum are positive or zero. Since the Auger peaks are separated by zeros after background removal, the method is well suited for peak finding and identification.Dedicated to Professor Dr. H. Seiler on the occasion of his 65th birthday 相似文献
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The dispersive component of the surface free energy
d
s
of glass fibers and their acid-base interaction can be evaluated by the measurement of specific retention volumes of several kinds of probe molecules by use of an inverse gas chromatography. The effect of the treatment of glass fibers with silane-coupling agents was also evaluated. The specific retention volumes of n-alkanes changed linearly with theirC number or vapor pressure. Those of polar molecules varied with their donor number (DN) or acceptor number (AN). The
s
d
values and electron-accepting or donating abilities depended upon the kind of functional groups contained in the coupling agents. 相似文献
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Amorphous ribbons of Mg-Y-TM-[Ag] (TM: Cu, Ni), prepared by melt spinning, were subjected to electrochemical investigations. Oxide layers formed anodically under potentiostatic control in different electrolytes were investigated by AES and sputter depth profiling. Problems and specific features of characterization of the composition of oxide layers and amorphous ternary or quaternary Mg-based alloys have been investigated. In the alloys the Mg(KL(23)L(23)) peak exhibits a different shape compared to that in the pure element. Analysis of the peak of elastically scattered electrons proved the absence of plasmon loss features, characteristic of pure Mg, in the alloy. A different loss feature emerges in Mg(KL(23)L(23)) and Cu(L(23)VV). The system Mg-Y-TM-[Ag] suffers preferential sputtering. Depletion of Mg and enrichment of TM and Y are found. This is attributed mainly to the preferential sputtering of Mg. Thickness and composition of the formed oxide layer depend on the electrochemical treatment. After removing the oxide by sputtering the concentration of the underlying alloy was found to be affected by the treatment. 相似文献
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Itani H Duchoslav J Arndt M Steck T Gerdenitsch J Faderl J Preis K Winkler W Stifter D 《Analytical and bioanalytical chemistry》2012,403(3):663-673
Zn–Cr alloyed coatings electrochemically deposited are of high interest for leading steel manufacturing companies because
of their novel properties and high corrosion resistance compared with conventional Zn coatings on steel. For tuning and optimizing
the properties of the electrodeposited Zn–Cr coatings, a broad range of the deposition conditions must be studied. For this
reason, two different types of material were investigated in this study, one with a low electrolyte temperature and one with
an elevated electrolyte pH, compared with the standard values. Because different corrosion performance and delamination behaviour
of the layers were observed for the two types, advanced surface analysis was conducted to understand the origin of this behaviour
and to discover differences in the formation of the coatings. The topmost surface, the shallow subsurface region, and the
whole bulk down to the coating–steel interface surface were analysed in detail by X-ray photoelectron spectroscopy (XPS) and
high-resolution scanning Auger electron spectroscopy to determine the elemental and the chemical composition. For better understanding
of the resulting layer structure, multiple reference samples and materials were measured and their Auger and XPS spectra were
fitted to the experimental data. The results showed that one coating type is composed of metallic Zn and Cr, with oxide residing
only on the surface and interface, whereas the other type contains significant amounts of Zn and Cr oxides throughout the
whole coating thickness. 相似文献