Search results for " interfaces"
showing 10 items of 1158 documents
Dual Ni/Ni-Co electrodeposited coatings for improved erosion-corrosion behaviour
2019
Abstract Industrial applications of hydrophobic metallic coatings are limited to durability of their surface structures against detrimental effects of the surrounding environments. In the present research, the life-long of the hierarchical structure of hydrophobic nickel coating in an erosive-corrosive solution was investigated. The effect of alloying with cobalt on strengthening the hierarchical structures was also investigated. In this regard, highly hydrophobic Ni/Ni, Ni-Co/Ni-Co, dual Ni/Ni-Co and dual Ni-Co/Ni coatings with rough hierarchical structures were electrodeposited. In situ electrochemical measurements were performed to investigate changes in corrosion resistance and hydropho…
Spatially resolved nanostructural transformation in graphite under femtosecond laser irradiation
2015
Abstract A polycrystalline graphite target was irradiated using infrared (800 nm) femtosecond (120 fs) laser pulses of different energies. Increase of sp 3 bonds percentage and possible diamond crystal formation were investigated ‘in-depth’ and on the irradiated surfaces. Synchrotron X-ray diffraction pattern have shown the presence of a diamond peak in one of the irradiated zones while X-ray photoelectron spectroscopy investigations have shown an increasing tendency of the sp 3 percent in the low power irradiated areas and similarly ‘in the depth’ of the higher power irradiated zones. Multiple wavelength Micro-Raman investigations have confirmed this trend along with an ‘in-depth’ (but not…
XPS study of pumice-supported palladium and platinum catalysts
1992
An XPS study has been performed on samples of monometallic of palladium and platinum and on bimetallic Pd-Pt catalysts supported on pumice. A negative shift of about 0.5 eV in the Pd 3d and Pt 4f binding energies of the catalysis relative to the energies of the same levels in the pure metals suggested an increase in the electron density in both metals. A quantitative XPS analysis indicated that the supported metals did not modify the surface atomic composition of pumice
Compaction of tungsten oxide films by ion-beam irradiation
1993
Abstract Evaporated amorphous tungsten oxide films with low densities, deposited on different substrates, have been irradiated with various types of ions of different energies up to 30 MeV, and with fluences up to 10 18 cm −2 . Compaction of the films up to nearly the bulk density was observed. No changes of the stoichiometry as determined by various ion-beam analysis techniques were detectable. Raman measurements showed that ion-beam-modified films are also amorphous, but have a different microstructure from as-deposited films. The irradiated films have a higher refractive index than the as-deposited films. A low threshold for the compaction effect of a few times 10 12 ions cm −2 was found…
Interdependence of structural and electrical properties in tantalum/tantalum oxide multilayers
2013
International audience; Dc reactive sputtering was used to deposit tantalum metal/oxide periodic nanometric multilayers using the innovative technique namely, the reactive gas pulsing process (RGPP). Different pulsing periods were used for each deposition to produce metal-oxide periodic alternations included between 5 and 80 nm. Structure, crystallinity and chemical composition of these films were systematically investigated by Transmission Electron Microscopy (TEM) and Energy-dispersive X-ray (EDX) spectroscopy techniques. Moreover, electrical properties were also studied by the Van der Pauw technique.
A photoemission study of molybdenum hexacarbonyl adsorption and decomposition on TiO2(110) surface.
2007
International audience; The adsorption and decomposition of molybdenum hexacarbonyl on (110) TiO2 surfaces were studied using both core levels and valence band photoemission spectroscopies. It was found that after an adsorption at 140 K, when going back to room temperature, only a small part of molybdenum compounds, previously present at low temperature, remained on the TiO2 surface. This indicates that the desorption temperature on such a surface is lower than the decomposition one. The use of photon irradiation to decompose the hexacarbonyl molecule was also studied. It was shown that during such a decomposition molecular fragments were chemisorbed on the surface allowing a higher amount …
Structural and electrical properties in tungsten/tungsten oxide multilayers
2014
International audience; Tungsten and tungsten oxide periodic nanometric multilayers have been deposited by DC reactive sputtering using the reactive gas pulsing process. Different pulsing periods have been used for each deposition to produce metal-oxide periodic alternations ranging from 3.3 to 71.5 nm. The morphology, crystallinity and chemical composition of these films have been investigated by transmission electron microscopy and energy-dispersive X-ray spectroscopy techniques. The produced multilayers exhibited an amorphous structure and the composition stability of WO3 sub-layers has been pointed out. Moreover, electrical properties have also been studied by the van der Pauw technique…
Investigation of La2O3 and/or (Co,Mn)3O4 deposits on Crofer22APU for the SOFC interconnect application
2009
International audience; Chromia forming alloys (stainless steels) are among the best candidates for SOFC interconnects. However, problems of decreasing electronic conductivity during high temperature service and volatility of chromium oxide scales need to be solved. Electronically conductive surface coatings, which also reduce oxide scale growth and chromium volatility, are needed to improve stainless steel interconnects. The goal of this study is to investigate combinations of lanthanum oxide (La2O3) and cobalt manganese oxide ((Co,Mn)3O4) coatings on Crofer22APU stainless steel. Thin film coatings of La2O3 (~200 nm) and Co,Mn (1:1) (~2 mm) were deposited via metal organic chemical vapor d…
Phosphites as precursors in atomic layer deposition thin film synthesis
2021
We here demonstrate a new route for deposition of phosphorous based materials by atomic layer deposition (ALD) using the phosphites Me3PO3 or Et3PO3 as precursors. These contain phosphorous in the oxidation state (III) and are open for deposition of reduced phases by ALD. We have investigated their applicability for the synthesis of LiPO and AlPO materials and characterized their growth by means of in situ quartz crystal microbalance. Phosphites are good alternatives to the established phosphate-based synthesis routes as they have high vapor pressure and are compatible with water as a coreactant during deposition. The deposited materials have been characterized using XPS, x-ray fluorescence…
Detection of planar defects caused by ion irradiation in Si using molecular dynamics
2007
We have analyzed the evolution of defects caused by self-irradiation of crystalline silicon. A classical molecular dynamics simulation was followed by defect analysis using the Pixel Mapping (PM) method. The PM identified {311} planar defects and long-chain structures of the so-called interstitial chains following low energy (1 keV) ion impact. The areal density obtained from simulation of self-interstitial atoms was about two thirds of that of experiments reported in the literature [Jpn. J. Appl. Phys. 30 (1991) L639], while the atomic configuration on respective planes agreed exactly.