Search results for "Titanium"
showing 10 items of 878 documents
Assessment of protection treatments for carbonatic stone using nanocomposite coatings
2020
In this paper the effect of the application of four kinds of polymer dispersions containing nanoparticles, used as protectives, on two type of carbonatic lithotypes, White Noto and Comiso stone, is reported. The study was conducted by analysing the contribution of each component of the system. After the structural characterization of the coating itself, the performance of those colloidal systems has been studied upon application on the calcarenites, preferring non-invasive techniques and microdestructive techniques. Effect of the nanoparticles presence on hydrorepellency and roughness of the stone surface and on chromatic changes has also been considered. The tests conducted have proven tha…
Laser Cladding of TiC for Better Titanium Components
2011
Pure commercial titanium is widely used because of its high corrosion resistance and lower cost compared with other titanium alloys, in particular when there is no high wear requirements. Nevertheless, the wear resistance is poor and surface damage usually occurs in areas under contact loadings. Laser cladding is a suitable technique for manufacturing precise and defect free coatings of a dissimilar material with higher wear and corrosion resistance. In this work a good understanding of laser metal deposition mechanisms allowed to obtain defect free coatings of Ti6Al4V and TiC metal matrix composite (MMC) using a flash lamp pumped Nd:YAG laser of 1 kW. A complete investigation of the proces…
On the mechanisms involved in the tensile strength of a dissimilar Ti6Al4V/316L laser welded assembly
2021
International audience; The aim of the present work is to analyze the thermomechanical behavior of dissimilar laser seams by means of FE modeling. The case of a Ti6Al4V/316L assembly with vanadium insert was considered. Effective mechanical properties of the main materials and cords were first estimated from NHT measurements. Modeling of the double pass laser welding process was performed first by considering shrinking of the two weld seams during manufacturing, to get the residual stress state in the welded assembly. Modeling of the tensile test was performed in a second step to study the assembly behavior during loading. In these modeling results, the mesh was the cross-section of the mic…
Optical properties of TiO2 suspensions: Influence of pH and powder concentration on mean particle size
2007
WOS: 000250584100025
Polystyrene nanoparticle-templated hollow titania nanosphere monolayers as ordered scaffolds
2018
We report a novel multi-step method for the preparation of ordered mesoporous titania scaffolds and show an illustrative example of their application to solar cells. The method is based on (monolayer) colloidal nanosphere lithography that makes use of polystyrene nanoparticles organised at a water–air interface and subsequently transferred onto a solid substrate. A titania precursor solution (titanium(IV) isopropoxide in ethanol) is then drop-cast onto the monolayer and left to “incubate” overnight. Surprisingly, instead of the expected inverse monolayer-structure, a subsequent calcination step of the precursor yields an ordered monolayer of hollow titania nanospheres with a wall thickness …
X-ray absorption study of Ce?Ti oxide films
2001
Abstract X-ray absorption measurements at the Ce L 3 , L 1 and Ti K-edges have been done to study local structure and electronic properties of CeO 2 –TiO 2 thin films produced by reactive d.c. magnetron sputtering. The local environment around titanium and cerium ions can be described as pyramid-like and cube-like polyhedra, respectively, and the films are amorphous (correlation radius about 10 A). The analysis of Ce L 3 -edge XANES data has shown that the position of the Ce 4f 1 5d and 4f 0 5d states progressively shift towards lower energies with decreasing cerium dioxide content in the thin films.
The lateral variation of solid state reactions at surfaces studied by means of photoemission electron microscopy: formation of titanium silicides
2001
The alloying and oxygen reduction at titanium silicon interfaces were studied by means of photoemission microscopy. The microscopic chemical composition of the sample surface was characterised by means of imaging X-ray absorption. The silicide formation was studied at clean and oxidised silicon substrates both covered with micron-sized titanium patterns.
A Route toward (Aminomethyl)cyclopentadienide Ligands and Their Group 4 Metal Complexes
2018
International audience
Titanium and zirconium complexes containing the new 2,3-dimethyl-1,4-diphenylcyclopentadienyl ligand. Synthesis, characterization and polymerization …
2004
Abstract An easy and inexpensive three-step synthesis of new 2,3-dimethyl-1,4-diphenylcyclopentadiene (3) ligand and the titanium and zirconium homometallocene dichlorides [TiCl2(η5-C5H-2,3-Me2-1,4-Ph2)2] (4), [ZrCl2(η5-C5H-2,3-Me2-1,4-Ph2)2] (5), and the mixed ligand zirconium complex [ZrCl2(η5-C5H-2,3-Me2-1,4-Ph2)(η5-C5H5)] (6) prepared thereof are described. The polymerization of ethene using 4–6/MAO catalysts revealed that zirconocene complexes 5 and 6 displayed moderate and high activity, respectively, whereas the titanium catalyst 4/MAO was inactive. The crystal structures of 4 and 5 were determined by X-ray crystallography.
Complexes of titanium and zirconium containing a tridentate linked amido–cyclopentadienyl ligand with a soft donor group: synthesis, structure, and e…
1999
Abstract Group 4 metal complexes M(η5:η1-C5R4SiMe2NCH2CH2SMe)Cl2 (R=H, M=Ti; R=Me, M=Ti, Zr) containing the thioether-functionalized linked amido–cyclopentadienyl ligand were synthesized and characterized by 1H- and 13C-NMR spectroscopy, mass spectrometry, and elemental analysis. The crystal structures of the complexes Ti(η5:η1-C5H4SiMe2NCH2CH2SMe)Cl2 and Zr(η5:η1:η1-C5Me4SiMe2NCH2CH2SMe)Cl2 were determined by single-crystal X-ray diffraction studies. The titanium complex is a conventional three-legged piano-stool molecule without an intramolecular interaction between the sulfur donor group and the titanium center, whereas the zirconium complex adopts a trigonal bipyramidal structure, with …