Publications by Philippe Buffat

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The effects of 107 MeV Kr-84(17+) ion irradiation on YBa2Cu3O7-x-based second-generation coated conductors were investigated using a combination of transmission electron microscopy, diffraction and X-ray energy dispersive spectrometry. Defects 3-5 nm in di ...

The precipitation state of an Al-4 wt% Cu-1 wt% Mg-Ag alloy reinforced with SiC particles fabricated by squeeze casting is studied by transmission electron microscopy. As a consequence of an interfacial reaction the precipitation of the characteristic phases of the unreinforced alloy, Ω and S′, is suppressed and substituted by a new precipitation consisting of isolated nanoscaled rod-shaped precipitates and θ′ plates decorated with a further type of rod-shaped precipitates. These precipitates are the Q-Al5C

Diamond tips are attractive tools for nanoscience because of their hardness and, when doped chemical vapor deposited (CVD) diamond is used, their electrical conductivity. In this article, devices based on CVD diamond coated silicon tips and molded diamond pyramids are described. A new type of tip, with a controlled selectively deposited diamond coating, on its upper part only, is presented, which will be useful for integration with actuators, sensors, etc. Pyramidal diamond tips with cantilevers have been m

The β′ and QC rod-shaped precipitates, observed in the Al-Mg-Si and Al-Cu-Mg-Si alloys, respectively, are studied by transmission electron microscopy (TEM). Superstructure images and microdiffraction patterns confirm the likeness between the β′ and QC phases. The microdiffraction patterns are compared with computed ones in the aim to refine a previous structural model based on the existence of a latent disordered phase QP constituted by sub-unit triangular clusters. The space group of the β′ and QC phase is

High-resolution transmission electron microscopy (HRTEM) and HRTEM simulation by the Bloch wave method (JEMS) are used to determine the structure and thickness of micro- and nanocrystals of biominerals and hydroxyapatite grown from aqueous solutions. It is established that thin (from one to several lattice parameters) crystals, including hydroxyapatite in mineralized biological tissues, are usually formed in low-temperature (up to 40degreesC) solutions. Relatively thick (up to several tens of lattice parame

The microstructure, chemical and phase composition of the hard Ni-P-Ti layer formed on the Ti-6Al-4V alloy after duplex surface treatment were investigated by light microscopy, X-ray diffraction, scanning electron microscopy and analytical/high-resolution ...

The spatial evolution of compositions and sub-structures inside focused-electron-beam-deposited tips from dicobalt-octacarbonyl Co2(CO)8 precursor at 25 keV and varying beam current (20 pA - 3 A) is extensively studied for the first time by means of energy ...

Nano- and thin-film technologies based on novel systems associating metals particles to polymer matrix open a broad range of different applications. Such composites were found to be more efficient and safe, for instance, in biomedical needs. The Ag/poly(N- ...

The structure of Al, Ge, Mo-doped Higher Manganese Silicide (HMS) crystals with the general formulas Mn(Si0.99Ge0.01)(1.75), Mn(Si0.995Ge0.005)(1.75) and (Mn0.98Mo0.02)(Si0.98Ge0.02)(1.75)Al-0.01 was investigated by scanning and transmission electr ...

Microstructure and chemical composition of the hard Ni–P–Ti layer formed on the Ti–6Al–4V alloy after duplex surface treatment were investigated by light microscopy, X-ray diffraction, scanning electron microscopy and analytical/high resolution transmissio ...

A structural analysis of the Ru—RuOx/TiO2 catalyst has been carried out. This catalyst is active for CO2 methanation at low temperatures. The preparation conditions are critical in generating the selective dispersion of the metallic particles on rutile crystallites in TiO2-P25. This distribution is limited to the most active samples (CH4 rate = 70 µl/h). On reducing the catalyst at 500°C, in 1 : 1 Ar + H2 for 1 h, Ru metal particles of not, vert, similar 5 nm have been obtained. These particles have a perfe

The microstructure of titanium alloys (Ti–1Al–1Mn, Ti–6Al–4V) nitrided under glow discharge was characterised using light microscopy, X-ray diffraction and analytical electron microscopy. The investigations revealed a complex multilayered microstructure pr ...

The structural characteristics of CdTe/CdS thin-film heterojunctions are investigated. The studied heterojunctions were obtained by successive thermal evaporation under vacuum onto unheated SnO2 coated glass substrates of CdS and CdTe films, respectively. ...

Gold nanoparticles were supported on activated carbon fibers (ACF) using the aq. soln. of [Au(en)2]Cl3 via ion-exchange with surface hydroxyl groups followed by redn. in H2. The obtained catalysts were tested in CO oxidn. at room temp. Surface phenolic groups fix Au3+-ions leading to the formation of small Au particles (.apprx.5 nm) after the redn. with high activity in the reaction. AAS, TPD, HRTEM/EDAX and XPS were used for characterization of the catalysts and supports.

High resolution transmission electron microscopy (HRTEM) and X-ray energy dispersive spectroscopy (EDS) were applied to study the structure of hydroxyapatite (HAP) coatings deposited by plasma spraying on different substrates (Cu, Cr, Ni, NaCl, BaF2). Coatings were obtained with a 13.56 MHz RF argon plasma at 1 Pa by placing a HAP target as the RF electrode. The typical rate of coating formation was about 1.0 - 1.5 nm/s and the total thickness was 350 - 400 nm. For all coating conditions and substrates inve

High-Resolution Electron Microscopy observations of gold particles are compared with images calculated using the multislice method for both regular f.c.c.-cuboctahedron- and Multiply-Twinned Particles -icosahedron, decahedron-. Although simulated for idea

The resolution of TEM fluorescent screens is one of the limiting factors for the acquisition of CCTV images with a high definition (1024 x 1024 pixels or more). Our comparison between YAG single crystal and ZnCdS powder phosphors screens shows that this latter offers a better resolution at 100 and 300 kV accelerating voltage. Nevertheless, still higher resoultion are necessary.

We have analyzed the influence of the two different Ti doping methods on the superconducting properties of bronze processed (Nb,Ta,Ti)3Sn multifilamentary wires with identical configuration, consisting of a Nb7.5wt.%Ta alloy processed to 14641 filaments of ...

Philippe Buffat

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Structure analysis of the YBCO layer in Ag/YBCO/metal oxide buffer/Hastelloy composite tape before and after 107 MeV Kr17+ irradiation

Structural phase transition in Al-Cu-Mg-Si alloys by transmission electron microscopy study on an Al-4wt% Cu-1 wt% alloy reinforced by SiC particles

CVD diamond probes for nanotechnology

Transmission electron microscopy study of the β′ phase (Al-Mg-Si alloys) and QC phase (Al-Cu-Mg-Si alloys): ordering mechanism and crystallographic structure

HRTEM simulation in determination of thickness and grain misorientation for hydroxyapatite crystals

Analytical transmission electron microscopy and electron diffraction for characterization of multiphase Ni-P-Ti surface layer on Ti-6Al-4V alloy

Cross section investigations of compositions and sub-structures of tips obtained by focused electron beam induced deposition

Stability of Ag nanoparticles dispersed in amphiphilic organic matrix

Structure of precipitates and orientation relationships in Al, Ge, Mo-doped higher manganese silicide crystals

Microstructure and properties of hard layers formed by duplex surface treatment containing nickel and phosphorus on a titanium-base alloy

The structure of ruthenium supported on titania: a catalyst for low-temperature methanation of carbon dioxide

Transmission electron microscopy and atomic force microscopy characterisation of titanium-base alloys nitrided under glow discharge

Preparation and structural characterization of thin-film CdTe/CdS heterojunctions

Gold nanoparticles on activated carbon fibers: Role of carbon surface groups for controlling the Au-particle size and catalytic activity

Nanostructure of hydroxyapatite coatings sprayed in argon plasma

The structure determination of small gold particles by high-resolution electron microscopy (HREM): image simulation and observations

A comparison between ZnCdS and YAG fluorescent screens from TEM

Erratum to “Preparation, stabilization and characterization of TiO2 on thin polyethylene films (LDPE). Photocatalytic applications"

The influence of Ti doping methods on the high field performance of (Nb, Ta, Ti)3Sn multifilamentary wires using Osprey bronze

Electron microscopy for investigation of order/disorder in bone structure