58 research outputs found
Effect of external stress on the Fe–Cr phase separation in 15-5 PH and Fe–15Cr–5Ni alloys
The effect on Fe–Cr phase separation of a uniaxial stress during thermal ageing at 4251C is investigated on a Fe–15Cr–5Ni steel, a model alloy of commercial 15-5 PH steel. The applied stress is shown to accelerate the ageing kinetics, and influence the morphology of Cr rich domains. A dependence of the phase separation decomposition kinetics on the relative orientations of the load and the crystal local orientation has also been observed
Nanoporous Ge thin film production combining Ge sputtering and dopant implantation
International audienceIn this work a novel process allowing for the production of nanoporous Ge thin films is presented. This process uses the combination of two techniques: Ge sputtering on SiO 2 and dopant ion implantation. The process entails four successive steps: (i) Ge sputtering on SiO 2 , (ii) implantation preannealing, (iii) high-dose dopant implantation, and (iv) implantation postannealing. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology of the Ge film at different process steps under different postannealing conditions. For the same postannealing conditions, the Ge film topology was shown to be similar for different implantation doses and different dopants. However, the film topology can be controlled by adjusting the postannealing conditions
Room-temperature magnetoelectric effect in lead-free multiferroic BaCaTiSnO-CoFeO particulate composites
Multiferroic particulate composites
BaCaTiSnO-CoFeO with (
= 0.1, 0.2, 0.3, 0.4 and 0.5) have been prepared by mechanical mixing of the
calcined and milled individual ferroic phases. X-ray diffraction and Raman
spectroscopy analysis confirmed the formation of both perovskite
BaCaTiSnO (BCTSn) and spinel
CoFeO (CFO) phases without the presence of additional phases. The
morphological properties of the composites were provided by using Field
Emission Scanning Electron Microscopy. The BCTSn-CFO composites exhibit
multiferroic behavior at room temperature, as evidenced by ferroelectric and
ferromagnetic hysteresis loops. The magnetoelectric (ME) coupling was measured
under a magnetic field up to 10 kOe and the maximum ME response found to be 0.1
mV /cm/ Oe for the composition 0.7 BCTSn-0.3 CFO exhibiting a high degree of
pseudo-cubicity and large density
Magnetoelectric coupling in multiferroic CFO/BCTSn core shell nanofibers elaborated by co-axial electrospinning method
Multiferroic CoFe2O4-Ba0.95Ca0.05Ti0.89Sn0.11O3 core-shell nanofibers
(CFO@BCTSn NFs) were synthesized by a sol-gel co-axial electrospinning
technique. The scanning electron microscope and transmission electron
microscope were used to check nanofibers' core-shell structure/configuration.
X-ray diffraction and a high-resolution transmission electron microscope were
used to confirm the spinel structure of CFO and the perovskite structure of
BCTSn. The magnetic character of the resultant CFO@BCTSn NFs was determined by
SQUID magnetometry. The piezoelectricity was verified using piezo-response
force microscopy, which revealed an entirely covered ferroelectric shell
outline, in accordance with SEM and TEM observations. The magnetoelectric (ME)
coefficient was measured as a function of the applied external DC magnetic
field. The maximum ME coefficient obtained for the CFO@BCTSn NFs was 346 mV
cm-1 Oe-1. The high magnetoelectric coupling suggests that CFO@BCTSn NFs could
be a promising candidate for magnetic field sensor and magnetoelectric device
applications
Nanoporous Ge thin film production combining Ge sputtering and dopant implantation
In this work a novel process allowing for the production of nanoporous Ge thin films is presented. This process uses the combination of two techniques: Ge sputtering on SiO2 and dopant ion implantation. The process entails four successive steps: (i) Ge sputtering on SiO2, (ii) implantation preannealing, (iii) high-dose dopant implantation, and (iv) implantation postannealing. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology of the Ge film at different process steps under different postannealing conditions. For the same postannealing conditions, the Ge film topology was shown to be similar for different implantation doses and different dopants. However, the film topology can be controlled by adjusting the postannealing conditions
Atom probe tomographic study of L10 martensite in a Pt-modified NiCoCrAlYTa bond coating
The L10 martensite formed in a Pt-modified NiCoCrAlYTa bond coating has been investigated by atom probe tomography. It was found that obvious segregation of Co and Cr occurred in the micro-twins zone inside the martensite lath. Based upon the compositional analysis, it is known that Pt destabilizes the β phase and Co and Cr act as β stabilizers with respect to the β→L10 martensitic transformation. In addition, some α-Cr particles precipitated inside the martensite lath
Etude de la redistribution des dopants et des éléments d'alliages lors de la formation des siliciures
The objective of this study is to characterize the redistribution of alloys elements and of dopants during first stages of formation of Ni silicides. For that, we studied the nature, the sequence and the kinetics of the formed phases, initially for the binary systems Pd/Si, Pt/Si and Ni/Si, then for the ternary systems (Ni, Pt)/Si and Ni/(Si, As) being of technological interest for the nanoelectronic industry. Thus, we coupled original techniques of characterization (differential scanning calorimetry on thin films, tomographic atomic probe, x-rays diffraction in situ) to measure the redistribution of Pt in the formed phases and their growth kinetic. We could develop a model to describe the first stages of growth of these alloyed silicides and to deduce the mechanisms brought into play as well as the factors limiting the redistribution of the alloy elements and the dopants.L'objectif de cette étude est de caractériser la redistribution d'éléments d'alliages et de dopants au cours des premiers stades de formation des siliciures de Ni. Pour cela, nous avons étudié la nature, la séquence et la cinétique des phases formées, dans un premier temps pour les systèmes binaires Pd/Si, Pt/Si et Ni/Si, puis pour les systèmes ternaires (Ni,Pt)/Si et Ni/(Si, As) présentant un intérêt technologique pour la nanoélectronique. Ainsi, nous avons couplé des techniques de caractérisation originales (calorimétrie différentielle à balayage sur films minces, sonde atomique tomographique, diffraction des rayons X in situ) pour mesurer la redistribution du Pt dans les phases formées et leurs cinétiques de croissance. Nous avons pu développer un modèle pour décrire les premiers stades de croissance de ces siliciures alliés et dégager les mécanismes mis en jeu ainsi que les facteurs limitant la redistribution des éléments d'alliage et des dopants
Etude de la redistribution des dopants et des éléments d'alliages lors de la formution des siliciures
L'objectif de cette étude est de caractériser la redistribution d'éléments d'alliages et de dopants au cours des premiers stades de formation des siliciures de Ni. Pour cela, nous avons étudié la nature, la séquence et la cinétique des phases formées, dans un premier temps pour les systèmes binaires Pd/Si, Pt/Si et Ni/Si, puis pour les systèmes ternaires (Ni,Pt)/Si et Ni/(Si,As) présentant un intérêt technologique pour la nanoélectronique. Ainsi, nous avons couplé des techniques de caractérisation originales (calorimétrie différentielle à balayage sur films minces, sonde atomique tomographique, diffraction des rayons X in situ) pour mesurer la redistribution du Pt dans les siliciures et leurs cinétiques de croissance. Nous avons pu modéliser les premiers stades de croissance de ces siliciures alliés et dégager les mécanismes mis en jeu ainsi que les facteurs limitant la redistribution des éléments d'alliage et des dopants.AIX-MARSEILLE3-BU Sc.St Jérô (130552102) / SudocSudocFranceF
Third International Symposium Nanomaterials: Microstructure and Properties (TRAMP19). Abstracts Book
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