Search results for "COATINGS"
showing 10 items of 2386 documents
Magnesium alloys laser (Nd:YAG) cladding and alloying with side injection of aluminium powder
2003
International audience; The development of the high purity magnesium alloys (such as WE43) incites the designers to reconsider them, and the car industry appears, these days, the most interested to use this kind of alloy. However, due to their ignitability and tendency to oxidation, magnesium alloys require surface treatments. A series of experiments was carried out in order to improve the corrosion resistance of two types of magnesium alloys, WE43 and ZE41. In most cases, the substrate surface was treated before laser interaction. Side injection of aluminium powder under a 3 kW cw Nd:YAG laser was employed. The deposited layers present very good bond properties. The resulting microstructur…
Magnesium alloys (WE43 and ZE41) characterisation for laser applications
2004
International audience; One of the most important parameters in laser treatment is the quantity of beam energy absorbed by the substrate. Despite its important role played in laser processes, this factor is rarely available for the laser sources wavelengths and at high temperatures reached during such treatments. A series of experiments were carried out in order to characterise, from this point of view, two types of magnesium alloys, WE43 and ZE41, often used in laser applications (cladding, alloying, welding, etc.). The results represent an important step in order to understand Mg-alloys behaviour under laser beam action.
MoSi2 laser cladding—A new experimental procedure: double-sided injection of MoSi2 and ZrO2
2003
International audience; In the last decade, development of low density advanced material systems for service at temperatures up to 1300 °C was one of the goals of many researches. This kind of material should mainly have moderate fracture toughness and should exhibit oxidation resistant behaviour at low and intermediate temperature. One of the most studied materials continues to be the intermetallic compound MoSi2. The molybdenum disilicide has been considered as an attractive candidate due to its melting point (2030 °C) and excellent oxidation resistance at high temperatures. The main problem associated with the MoSi2 layer synthesized using laser beam is the layer fragility. To avoid this…
EFFECT OF SURFACTANT AND SUBSTRATE TEMPERATURE ON THE GROWTH OF Ag FILMS ON A SAPPHIRE SURFACE
1997
The possibility of modification of the thin film growth on an insulating (sapphire) substrate by using a Ga monolayer as a "surfactant" was studied. We found that the films grown in this way are electrically conducting and can emit photoelectrons at much lower thickness than those deposited on a pure substrate. The surfactant stabilizes the positions of Ag atoms on the substrate surface and inhibits the coalescence of small nuclei into bigger islands, even when the film is annealed to 450 K. This fact may be very important for thin metal film technology.
Effect of kind and content of organo-modified clay on properties of PET nanocomposites
2011
In this work we report the properties of nanocomposite based on PET with two different samples of organically modified montmorillonites. In particular, we studied the effect of the filler concentration on morphology, rheology, and mechanical performance, focusing our attention on the effect of the degradation phenomena of the clay modifiers. The results indicate that at low clay level the morphology achieved is mainly intercalated. On increasing the filler level, coalescence and/or bad defragmentation phenomena induce a coarser morphology, as confirmed by XRD, SEM, and TEM observations. When a more polar organic modifier is used to modify the clay, the particle adhesion and distribution is …
Unveiling anion-induced folding in tripodal imidazolium receptors by ion-mobility mass spectrometry.
2021
The anion-induced folding of tripodal imidazolium receptors has been investigated by NMR spectroscopy, electrospray ionization ion mobility mass spectrometry and DFT calculations. Such folding can be switched by anion release upon collision induced dissociation.
Evidence of Spatially Inhomogeneous Electron Temperature in a Resonantly Excited Array of Bow-Tie Nanoantennas
2019
We studied the excitation of large-area Au bow-tie nanoantenna arrays, which we have fabricated on indium-tin-oxide (ITO)-coated glass substrates using colloidal lithography with nanoscale polystyr...
Two are not always better than one: ligand optimisation for long-living light-emitting electrochemical cells
2009
The complex [Ir(ppy)2(dpbpy)][PF6] (Hppy = 2-phenylpyridine, dpbpy = 6,6'-diphenyl-2,2'-bipyridine) has been prepared and evaluated as an electroluminescent component for light-emitting electrochemical cells (LECs); the complex exhibits two intramolecular face-to-face π-stacking interactions and long-lived LECs have been constructed; the device characteristics are not significantly improved in comparison to analogous LECs with 6-phenyl-2,2'-bipyridine. Costa Riquelme, Ruben Dario, Ruben.Costa@uv.es ; Orti Guillen, Enrique, Enrique.Orti@uv.es ; Bolink, Henk, Henk.Bolink@uv.es
Inhibitoren der Korrosion 31 (1). Beitrag zur Inhibierung der Korrosion von Zink und Messing
1986
Folgende als Inhibitoren der Korrosion vom Kupfer bewahrte Verbindungen wurden bei Korrosionsstudien mit Zink und Messing eingesetzt: 2-Aminopyrimidin (A), 5-Aminotetrazolmonohydrat (B), Benzotriazol (C), Kupferron (D), 2-Mercaptopyrimidin (E), 2-Mercaptothiazolin (F), 2-Methyl-4-amino-5-cyanopyrimidin (G), Tetrazin-B (H) und Xanthanwasserstoff (I). Bei Zinkblechen wird unter Standardbedingungen in Gegenwart der Verbindungen A, B, C, E und G im Laufe von 15 Tagen Totalkorrosion beobachtet. In Anwesenheit der Verbindungen D, F und H werden prozentuale Schutzwerte von 29%, 14% und 39% beobachtet. Ein differenzierteres Bild vermitteln die pH-statisch ermittelten Saureverbrauchs-Zeit-Kurven mit…
Xylochemicals and where to find them
2021
This article surveys a range of important platform and high value chemicals that may be considered primary and secondary 'xylochemicals'. A summary of identified xylochemical substances and their natural sources is provided in tabular form. In detail, this review is meant to provide useful assistance for the consideration of potential synthetic strategies using xylochemicals, new methodologies and the development of potentially sustainable, xylochemistry-based processes. It should support the transition from petroleum-based approaches and help to move towards more sustainability within the synthetic community. This feasible paradigm shift is demonstrated with the total synthesis of natural …