Search results for "Surfaces"
showing 10 items of 2837 documents
Anodic Electro Deposition of CeO2 and Co-Doped CeO2 Thin Films
2013
CeO2 and Co containing CeO2 thin films were deposited on indium tin oxide and stainless steel by anodic electrodeposition. Scanning electron microscopy showed that the films are flat and show globular morphology and cracks resulting from volume shrinking. According to XRD and Raman Spectroscopy pure ceria layers are crystalline, while the presence of Co induces the formation of amorphous films. The good adhesion and the compactness allowed the photoelectrochemical characterization of the films. A band gap value of 2.9 eV was estimated for CeO2, while slightly higher values (̃3.0 eV) were estimated for Co containing films. A mechanism for ceria anodic electrodeposition is proposed and discus…
Methods of controllable internal rupture in solids and liquids for obtaining atomically-clean surfaces and investigating their adhesion
1995
Controllable internal rupture (CIR) methods for obtaining atomically-clean solid surfaces and closed ultrahigh vacuum (UHV) space are described. A number of modifications of CIR methods have been developed. Their performance, characteristics and applications for investigation of adhesion are considered. CIR methods are based on the creation of virgin atomically-clean rupture surfaces in the bulk of solids during deformation of specially manufactured heterogeneous systems. For all modifications of the method, the samples have been manufactured in the form of vacuum-tight capsules and the investigation procedure has been carried out in atmospheric conditions. CIR methods, in addition to well-…
Small-pore driven high capacitance in a hierarchical carbon via carbonization of Ni-MOF-74 at low temperatures
2016
A hierarchical porous carbon prepared via direct carbonization of Ni-MOF-74 loaded with furfuryl alcohol at 450 °C displays high specific capacitance in comparison with other MOF-derived carbons as a result of the formation of micropores smaller than 1 nm.
Electroswitching of the single-molecule magnet behaviour in an octahedral spin crossover cobalt(ii) complex with a redox-active pyridinediimine ligand
2020
Thermal-assisted spin crossover and field-induced slow magnetic relaxation coexist in the solid state for the mononuclear cobalt(II) complex with the non-innocent 2,6-bis(N-4-methoxyphenylformimidoyl)pyridine ligand. One-electron oxidation of the paramagnetic low-spin CoII ion (SCo = 1/2) to the diamagnetic low-spin CoIII ion (SCo = 0) leads to the electroswitching of the slow magnetic relaxation in acetonitrile solution.
Electrochemical Analysis of Catalytic and Oxygen Interfacial Transfer Effects on MnO2 Deposited on Gold Electrodes
2018
[EN] A theoretical model for obtaining thermochemical and kinetic information on oxygen interfacial transfer in metal oxides deposited on gold electrodes, based in the voltammetry of immobilized particle methodology, is presented. It is applied to MnO2 microparticulate deposits on gold in contact with aqueous NaOH solution using the voltammetric signals for the oxidation of gold to gold oxide monolayer and its subsequent desorptive reduction. Assuming reversibility, voltammetric peak potentials permit to estimate a variation of Gibbs free energy of interfacial oxygen transfer of -32 +/- 3 kj mol(-1). Analysis of peak current data based on the Sharp-Hancock formalism of solid-state kinetics …
Molybdenum thin-film growth on rutile titanium dioxide ()
2002
Molybdenum films were deposited at room temperature on rutile TiO2(1 1 0) surfaces having different stoichiometries, surface roughnesses and crystallinities. The film structures and compositions and the substrate–film interfaces were investigated by X-ray diffraction, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. Different substrate pretreatments resulted in markedly different film and interface structures. Under the growth conditions studied, no amorphous molybdenum oxide interlayers were formed upon deposition in contrast to previous studies. Preferred (1 1 0) textured Mo films grew on both air-annealed and oxygen-bombarded substrates. While sh…
Microstructural and tribological study of Nd:YAG laser treated titanium plates.
2008
Abstract In this work, the fretting behaviour of pure Ti plates laser treated with a Nd:YAG pulsed laser was compared to that of untreated Ti plates. Fretting tests were done at room temperature without lubrication. The contact geometry was a cylinder (bearing steel) on a plane. The evolution of both the ratio, μ = Q / P , between the normal and the tangential forces, and the Fouvry's energy criterion ( A ) were recorded as a function of the number of fretting cycles, N . Energy dispersive spectrometry and micro-Raman spectroscopy were used to analyse the fretting scars. The oxidized layer formed by the laser treatment displayed a mixed slip regime as a function of N , and a smaller frettin…
Influence of the composition of titanium oxynitride layers on the fretting behavior of functionalized titanium substrates: PVD films versus surface l…
2014
International audience; Abstract In this work we compared the fretting behavior of pure titanium plates functionalized with titanium oxynitride surface layers, obtained by two methods: a Physical Vapor Deposition (PVD) method, reactive magnetron sputtering, and Surface Laser Treatments (SLT), under different mixtures of oxygen and nitrogen. The composition of the layers was determined by nuclear reaction analysis (NRA) and their structure was analyzed by Raman spectroscopy. PVD layers were TiN-like fcc layers, with an oxygen concentration going from 36 to 50 at.%. Three SLT layers were studied. The first one was a TiN-like layer containing ~28 at.% of oxygen. The second one was formed of di…
Aluminum and Gallium Substitution in Yttrium and Lutetium Aluminum–Gallium Garnets: Investigation by Single-Crystal NMR and TSL Methods
2016
The work reports the results on 71Ga and 27Al NMR investigation of the gallium and aluminum ions distribution over tetrahedral and octahedral positions in the Y3Al5−x GaxO12:Ce single crystals and Lu3Al5−xGaxO12:Ce single-crystalline epitaxial films. The gallium content x varies between 0 and 5 in crystals and between 0.3 and 2 in films.. We find that in both the Y- and Lu-based solid solutions the larger gallium ions are preferably located at the tetrahedral position while the smaller aluminum ions prefer the octahedral position of the garnet host. Based on NMR data, the dependence of fractional occupation parameters of the tetrahedral site of Ga and Al ions on the Ga content is determined…
Stabilization of MCM-41 by Pyrolytic Carbon Deposition
2000
A new method of surface modification which is effective in stabilizing silica grades of MCM-41 in the presence of water vapor is presented. It is shown by means of XRD, low-temperature nitrogen ads...