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1. Microstructure, Mechanical Properties, and Thermal Stability of Al-Al2O3 Nanocomposites Consolidated by ECAP or SPS from Milled Powders

Author

Antoine Lacour-Gogny-Goubert, Véronique Doquet, Marc Novelli, Alexandre Tanguy, Simon Hallais, Julie Bourgon, Benjamin Villeroy, and Roxane Massion

Subjects
metal matrix nanocomposites, powder consolidation, ECAP, SPS, thermal stability, thermal cracking, Mining engineering. Metallurgy, TN1-997
Abstract

Ultrafine-grained Al matrix nanocomposites, reinforced with Al2O3 nanoparticles, were produced from milled powders, either by equal channel angular pressing (ECAP), at room or high temperature, with or without back pressure, or by spark plasma sintering (SPS). Their microstructures, mechanical properties (compression, hardness, and sliding wear), and thermal stabilities (thermally induced softening and cracking) were compared, and the advantages and limitations of each process discussed on a scientific but also practical point of view. For the most successful set of process parameters, the yield stress in compression reached 380 MPa, the hardness, HV = 139, remained stable up to 500 °C, and the resistance to sliding wear was comparable to that of Al 5083, and better than that of Al 7075-T6. While the samples consolidated at high temperatures (by ECAP or SPS) showed a good thermal stability, those consolidated by ECAP at room temperature were prone to thermally induced softening and cracking, which was related to trapped and pressurized gases.

Published
2023
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2. Design and tensile properties of a bcc Ti-rich high-entropy alloy with transformation-induced plasticity

Author

Lola Lilensten, Jean-Philippe Couzinié, Julie Bourgon, Loïc Perrière, Guy Dirras, Frédéric Prima, and Ivan Guillot

Subjects
High-entropy alloy, mechanical properties, work hardening, martensitic phase transformation, titanium alloys, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

A new bcc Ti-rich high-entropy alloy (HEA) of composition Ti35Zr27.5Hf27.5Nb5Ta5 was designed using the ‘d-electron alloy design’ approach. The tensile behavior displays a marked transformation-induced plasticity effect resulting in a high normalized work-hardening rate of 0.103 without loss of ductility when compared to the reference composition Ti20Zr20Hf20Nb20Ta20. In this paper, a detailed microstructural analysis was performed to understand the deformation process, revealing architectural-type microstructures and a high volume fraction (65%) of internally twinned stress-induced martensite α″ after mechanical testing. This study opens the way to mechanical properties optimization and enhancement of titanium-based HEAs by combining multiple alloying designs. IMPACT STATEMENT For the first time, proof is given that transformation-induced plasticity was triggered in a bcc refractory high-entropy alloy, leading to a twofold increase in the normalized work-hardening rate.

Published
2017
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3. Dimethyl amino phenyl substituted silver phthalocyanine as a UV- and visible-light absorbing photoinitiator: in situ preparation of silver/polymer nanocomposites

Author

Louise Breloy, Yusuf Yagci, Julie Bourgon, Ismail Yilmaz, Martin Breza, Davy-Louis Versace, Vlasta Brezová, and Yusuf Alcay

Subjects
chemistry.chemical_classification, Materials science, Polymers and Plastics, Polymer nanocomposite, Organic Chemistry, Cationic polymerization, Bioengineering, Polymer, Photochemistry, Biochemistry, Photoinduced electron transfer, Silver nanoparticle, chemistry.chemical_compound, chemistry, Polymerization, Phthalocyanine, Photoinitiator
Abstract

A novel visible-light absorbing silver dimethyl amino phenyl substituted phthalocyanine photoinitiator (dmaph-Ag(II)Pc) for free-radical (FRP) and cationic (CP) polymerizations in laminate and under air is reported. The photoinduced electron transfer reactions of excited dmaph-Ag(II)Pc in the presence and absence of an iodonium salt (Iod) resulted in the formation of a Bronsted acid and radical species capable of initiating CP and FRP, respectively. The photophysical and photochemical properties of the photoinitiator are evaluated in detail by computational and spectroscopic investigations, and the kinetics of the polymerizations are studied. It was demonstrated that the described photoinitiating system is highly efficient in the simultaneous cationic or free-radical polymerization and silver ion reduction. The nanocomposites formed this way contain spherical shaped silver nanoparticles homogenously dispersed in the polymer matrix with a narrow size distribution between 5 and 20 nm.

Published
2021
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4. Well-Defined Titanium Complex for Free-Radical and Cationic Photopolymerizations under Visible Light and Photoinduction of Ti-Based Nanoparticles

Author

Takashi Kurogi, Vlasta Brezová, Daniel J. Mindiola, Louise Breloy, Agustin Rios de Anda, Davy-Louis Versace, Jean-Pierre Malval, and Julie Bourgon

Subjects
Nanocomposite, Materials science, Polymers and Plastics, Organic Chemistry, Cationic polymerization, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Photochemistry, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Photopolymer, Transmission electron microscopy, Scanning transmission electron microscopy, Materials Chemistry, Flash photolysis, Fourier transform infrared spectroscopy, 0210 nano-technology, Visible spectrum
Abstract

A quinoline-derived titanium complex (TiQ) is shown here to possess remarkable photosensitizing properties when treated with an iodonium salt (Iod) to initiate, under visible light irradiation, (i) the free-radical photopolymerization of acrylate monomer in aerated/laminate conditions, (ii) the cationic photopolymerization of epoxy monomer under air, and (iii) the in situ formation of Ti-based nanoparticles (NPs) inside coatings. The photochemical properties of the TiQ/Iod photoinitiating system have been probed by electron paramagnetic resonance, laser flash photolysis, and real-time Fourier transform infrared spectroscopy, which provide an insight into the possible radical/cationic pathways. The microstructural properties of the photosynthesized Ti-based NPs have been investigated by bright-field conventional transmission electron microscopy and high-angle annular dark-field scanning transmission electron microscopy. The macroscopic mechanical properties of the resulting nanocomposite reveal that the ge...

Published
2019
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5. Strain localization and delamination mechanism of cold-drawn pearlitic steel wires during torsion

Author

Pierre Morisot, Aurélie Jamoneau, Jean-Hubert Schmitt, Denis Solas, Julie Bourgon, Manuf Franc Pneumatic Michelin (M.F.P. Michelin), Société Michelin, Université Paris-Saclay, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), and CentraleSupélec

Subjects
010302 applied physics, Materials science, Mechanical Engineering, Delamination, Torsion (mechanics), Fracture mechanics, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Strain rate, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, [PHYS.MECA.MEMA]Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph], Mechanics of Materials, 0103 physical sciences, General Materials Science, Composite material, Pearlite, Deformation (engineering), 0210 nano-technology, Ductility, ComputingMilieux_MISCELLANEOUS, Stress concentration
Abstract

Pearlitic steel wires are cold-drawn in order to attain high strength from the alignment of the pearlite colonies along the wire axis, as well as achieve a considerable reduction in the thickness of the ferrite lamellae. However, this high level of stress, in addition to surface defects and residual stresses, drastically decreases the strain ductility in tension and often in torsion. A significant limitation in torsion is the nucleation and growth of delamination cracks which propagate along the wire. Although this fracture phenomenon has long been studied, its origin and the underlying mechanisms remain debatable. This paper presents new microstructure investigations of drawn wires during torsion. The stages of initiation and propagation are defined towards a chronology of the development phases of delamination cracks based on the study of the microstructure of cold-drawn pearlitic steel wires before and after torsion. The curling of the grains leads to the creation of long grooves on the surface of the wire. These grooves increase stress concentration during twisting, thus localizing the formation of shear bands. Deformation and strain rate are so high in these bands that nanograins (10–30 nm) are formed. The delamination then appears to be mainly due to the localization of the single-shear deformation along the wire axis with mainly intergranular crack propagation.

Published
2021
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6. Size-dependent hydrogen trapping in palladium nanoparticles

Author

Thomas Len, Wang Liu, Claudia Zlotea, Hakim Amara, Laurent Piccolo, Daniel Förster, Yann Magnin, Julie Bourgon, Franck Morfin, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Massachusetts Institute of Technology (MIT), LEM, UMR 104, CNRS-ONERA, Université Paris-Saclay (Laboratoire d'étude des microstructures), ONERA-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), IRCELYON-Catalyse Hétérogène pour la Transition Energétique (CATREN), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), DMAS, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, ANR-17-CE06-0008,UltraCat,Catalyseurs à base de métaux ultradispersés pour des applications liées à l'énergie impliquant l'hydrogène(2017), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL)

Subjects
Materials science, Hydrogen, Binding energy, chemistry.chemical_element, 02 engineering and technology, Trapping, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, DFT calculations, 01 natural sciences, Desorption, Interstitial defect, [CHIM.CRIS]Chemical Sciences/Cristallography, General Materials Science, in situ XRD, Extended X-ray absorption fine structure, Renewable Energy, Sustainability and the Environment, hydrogen absorption, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, in situ EXAFS, hydrogen desorption, 0104 chemical sciences, Pd nanoparticles, chemistry, Chemical physics, tight-binding modelling, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Density functional theory, Particle size, 0210 nano-technology
Abstract

International audience; We report an experimental study, supported by a theoretical approach based on simulations, to explore the phenomenon of H trapping in small Pd nanoparticles. Hydrogen absorption/desorption of a series of Pd nanoparticles with different average sizes (6.0, 2.0 and 1.4 nm) is only partially reversible, as proven by pressure-composition-isotherms at 25 °C. The irreversible H amount is trapped into strong interstitial sites. In situ EXAFS was employed to highlight the local structural changes and the H trapping inside the volume of Pd nanoparticles. We evidence a double size-dependent effect of H trapping inside Pd nanoparticles: the smaller the Pd particle size, the larger the amount of trapped H and the higher the binding energy experienced by H atoms. For example, 26% of the initial H capacity is trapped in Pd nanoparticles with 2.0 and 1.4 nm average sizes and a treatment under vacuum above 150 °C is needed to fully desorb the trapped H. To get atomic-scale insights into the location of the trapping sites, we perform both Density Functional Theory and Tight-Binding calculations. These simulations show that the strong H trapping sites are the octahedral interstitials located at the subsurface of Pd nanoparticles where high relaxations are possible. This finding might clarify the controversial role of "subsurface or bulk" hydrogen in Pd-based nano-catalysts in several hydrogenation reactions.

Published
2021
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8. Activation volume and the role of solute atoms in Al-Mg-Si alloy processed by equal channel angular extrusion

Author

Amel Soula, Jean Philippe Couzinié, Hanen Heni, Julie Bourgon, Yannick Champion, Nabil Njah, Faculté des Sciences de Sfax, Université de Sfax - University of Sfax, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Science et Ingénierie des Matériaux et Procédés (SIMaP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)

Subjects
Al-Mg-Si alloys, ASTAR, Mechanics of Materials, Mechanical Engineering, [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph], Materials Chemistry, Metals and Alloys, ECAE, Activation volume, imaging SRS
Abstract

International audience; Grain refinement to the sub-micron scale was found to enhance both strength and plasticity. In this size range, the micro-mechanisms of deformation are not yet sufficiently specified. In the present work, strain rate sensitivity was investigated in an Al-Mg-Si alloy processed by equal-channel angular extrusion. The microstructure was controlled by conventional transmission electron microscopy and orientation imaging-ASTAR. In the as-quenched state, deformation produces grains below 100 nm in size. The activation volume V was reduced to 70b 3. Based on published theoretical models, we have shown that in such alloy, pure grain boundary sliding cannot be revealed in the low-stress range, due to the intervention of solute atoms. Beyond, the stressdependence of V consists with an inverse Cottrell-Stokes behavior. This trend was confirmed by TEM which revealed dislocation activity and grain boundary emission. Ageing at 150 °C increases the contribution of GBS whereas the residual activation volume continues to be leveled.

Published
2021
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9. Bullet‐Shaped Magnetite Biomineralization Within a Magnetotactic Deltaproteobacterium: Implications for Magnetofossil Identification

Author

Julie Bourgon, Eric Leroy, Hitesh Changela, Lin Gu, Yongxin Pan, Xin’an Yang, Jinhua Li, Nicolas Menguy, Xiang Zhao, Peiyu Liu, and Andrew P. Roberts

Subjects
0303 health sciences, Atmospheric Science, Ecology, Magnetotactic bacteria, 030306 microbiology, Chemistry, Paleontology, Soil Science, Forestry, Nanotechnology, Aquatic Science, 03 medical and health sciences, chemistry.chemical_compound, Identification (biology), Magnetofossil, 030304 developmental biology, Water Science and Technology, Magnetite, Biomineralization
Published
2020
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10. Multiscale investigation of crack path and microstructural changes during liquid metal embrittlement of 304L austenitic steel in liquid sodium

Author

J. L. Courouau, Bassem Barkia, Julie Bourgon, Thierry Auger, Laboratoire de mécanique des sols, structures et matériaux (MSSMat), CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)

Subjects
Twinning, Materials science, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 020209 energy, General Chemical Engineering, 02 engineering and technology, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Corrosion, Liquid metal embrittlement, 0202 electrical engineering, electronic engineering, information engineering, General Materials Science, LME, Austenite, Crack path, Sodium, Metallurgy, General Chemistry, 021001 nanoscience & nanotechnology, Austenitic stainless steels, Martensitic transformation, Diffusionless transformation, Martensite, Fracture (geology), Deformation (engineering), 0210 nano-technology, Crystal twinning
Abstract

Fracture micro-mechanisms and crack path of embrittled austenitic steel 304L by liquid sodium strained at 4.2 × 10−7 m s−1 and 573 K are investigated underneath the fracture surface by transmission electron microscopy down to the nanoscale. Automated crystal orientation and phase mapping analyses show that abundant martensitic transformation (γ austenite → α’ martensite) as well as mechanical twinning occur during the deformation of austenite and play a major role in the fracture process. A correlation between the fracture surface features and the underlying microstructural interfaces is evidenced, strengthening the conclusion that liquid metal embrittlement by sodium of austenitic steels is basically an interfacial cracking phenomenon.

Published
2017
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11. High impact resistance of a TWIP β titanium alloy: linking the multi-scale deformation and fracture mechanisms

Author

Frédéric Prima, Julie Bourgon, Chloé Varenne, Anne-Françoise Gourgues-Lorenzon, Cédrik Brozek, Jacques Besson, Centre des Matériaux (MAT), MINES ParisTech - École nationale supérieure des mines de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, 020502 materials, Mechanical Engineering, Twip, Alloy, Titanium alloy, 02 engineering and technology, Plasticity, engineering.material, [SPI.MAT]Engineering Sciences [physics]/Materials, 0205 materials engineering, Mechanics of Materials, Fracture (geology), engineering, General Materials Science, Deformation (engineering), Composite material, Crystal twinning, ComputingMilieux_MISCELLANEOUS, Stress concentration
Abstract

Titanium alloys with twinning- and transformation-induced plasticity effects display promising mechanical properties, particularly, high impact toughness, unlike conventional titanium alloys. This work focuses on a highly strain-hardenable Ti–Cr–Sn alloy displaying both TRIP and TWIP effects upon quasi-static loading and an average impact toughness of 193 J/cm2, which represents nearly three times the measured value for commercial titanium alloys. To account for this extremely high impact toughness, fracture and deformation features were quantified at different scales using scanning electron microscopy and transmission electron microscopy, particularly a Precession-Assisted Crystal Orientation Mapping system. Examinations evidenced the major role of twins in the fracture process, even on a sub-micrometre scale. The high impact resistance and absorbed energy of this alloy are explained by the positive contribution of dynamical refinement of the β grains with sub-twinning structures, whereas severe stress concentration may eventually contribute to ductile fracture, at least locally.

Published
2020
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12. Bimetallic Cu–Rh Nanoparticles on Diazonium-Modified Carbon Powders for the Electrocatalytic Reduction of Nitrates

Author

Junxian Zhang, Julie Bourgon, Peyman Mirzaei, Eric Leroy, Youssef Snoussi, Christine Cachet-Vivier, Asma Bensghaier, Ouezna Hamouma, Atieh Aghajani, Mohamed M. Chehimi, Stéphane Bastide, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), MBA Water Treatment Chemicals Co., Ltd. (MBA), Laboratoire de génie des procédés - environnement - agroalimentaire (GEPEA), Université de Nantes (UN)-Ecole Nationale Vétérinaire, Agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
Carbon powder grafting, Nanoparticle, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Catalysis, Electrochemistry, General Materials Science, Graphite, Voltammetry, Bimetallic strip, Spectroscopy, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, Diazonium Compounds, nitrate electroreduction, Chemistry, Surfaces and Interfaces, cavity microelectrode, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, copper-rhodium nanoparticles, diazonium salt, Surface modification, Atomic ratio, 0210 nano-technology, Nuclear chemistry
Abstract

International audience; 4-benzenethiol-functionalized High Surface Area Graphite powder was prepared and decorated with bimetallic Cu 100-x Rh x nanoparticles (NPs) to serve as electrocatalysts for the reduction of nitrates. In the first step, the HSAG powder was grafted with in situ generated diazonium compounds from 4-aminothiophenol (ATP), in acidic medium using NaNO 2 for the diazotization process. The surface composition was tuned using different initial quantities of ATP. The surface XPS-determined S/C atomic ratio was found to increase stepwise with the initial amine quantity. In a second step, the grafted and untreated HSAG powders were decorated with Cu 100-x Rh x NPs by a wet chemical method and the elemental composition of the end composites assessed by EDS-SEM and ICP, whereas TEM and EDS-TEM served to characterize the NPs morphology and their composition at the nanometer scale. In all cases, the NP size was invariably found to be ~1.7 nm but with a size distribution becoming narrower under increasing grafting rate and the global composition enriched in copper. Voltammetry was performed with a cavity microelectrode to evaluate the electrocatalytic performances of the composites for nitrate reduction. Increasing diazonium grafting led to a progressive reduction of the peak current intensity and a shift of the peak potentials towards cathodic values. Maximum intensity was obtained for 0.005 µmol of diazonium salt per mg of HSAG, 2 with a gain of 40 % in comparison to the best untreated sample. This improvement and a change of the voltammogram characteristics after grafting seem to result from modifications of the local composition at the level of NPs that differs from the global composition. This work conclusively shows that diazonium surface modification is important not only to attach electrocatalytic NPs to carbon supports but also to provide narrower size distribution of the electrocatalysts together with finely tuned catalytic properties.

Published
2019
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13. Hydrogen sorption in TiZrNbHfTa high entropy alloy

Author

Ivan Guillot, Martin Sahlberg, Kasper T. Møller, Gustav Ek, Julie Bourgon, Etsuo Akiba, M. A. Sow, Torben R. Jensen, J-P Couzinie, Loïc Perrière, Claudia Zlotea, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Technologies d'Elaboration des Combustibles (LTEC), Service Plutonium Uranium et Actinides mineurs (SPUA), Département d'Etudes des Combustibles (DEC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Département d'Etudes des Combustibles (DEC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de mécanique des sols, structures et matériaux (MSSMat), CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), JRC Institute for Energy and Transport (IET), European Commission - Joint Research Centre [Petten], Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), and Kyushu University [Fukuoka]

Subjects
Materials science, Thermal desorption spectroscopy, STORAGE PROPERTIES, PHASE, 02 engineering and technology, Activation energy, Cubic crystal system, DIFFRACTION, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, Activation energy of hydrogen desorption, 01 natural sciences, 7. Clean energy, Hydrogen absorption/desorption, Tetragonal crystal system, Hydrogen storage, Desorption, Phase (matter), Materials Chemistry, ABSORPTION, [CHIM.CRIS]Chemical Sciences/Cristallography, ComputingMilieux_MISCELLANEOUS, Mechanical Engineering, High entropy alloys, Metals and Alloys, technology, industry, and agriculture, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Mechanics of Materials, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Physical chemistry, MICROSTRUCTURE, MGH2, 0210 nano-technology, In situ synchrotron X-ray diffraction
Abstract

High Entropy Alloys (HEA), where five or more elements are mixed together in near equiatomic ratios offer promising properties as hydrogen storage materials due to their ability to crystallize in simple cubic structures in the presence of large lattice strain originating from the different sizes of the atoms. In this work, the hydrogen absorption and desorption as well as the cycling properties of the TiZrNbHfTa HEA have been studied by in situ Synchrotron X-Ray diffraction, Pressure-Composition-Isotherm, Thermal Desorption Spectroscopy and Differential Scanning Calorimetry. The alloy crystallizes in a cubic bcc phase and undergoes a two-stage hydrogen absorption reaction to a fcc dihydride phase with an intermediate tetragonal monohydride, very similar to the V-H system. The hydrogen absorption/desorption in TiZrNbHfTa is completely reversible and the activation energy of desorption could be calculated. Furthermore, we have observed an interesting macrostructure following parallel planes after the formation of the dihydride phase, which is retained after desorption.

Published
2019
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14. Fast and scalable preparation of tetrahedrite for thermoelectrics via glass crystallization

Author

Annie Pradel, Gaëlle Delaizir, Julie Bourgon, C. Godart, Elsa B. Lopes, Bertrand Lenoir, Andrea Piarristeguy, Jean-Baptiste Vaney, Manuel F. C. Pereira, António Pereira Gonçalves, Eric Alleno, Judith Monnier, Instituto Superior Técnico Universidade de Lisboa (C2TN), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Centro de Recursos Naturais e Ambiente (CERENA), Instituto Superior Técnico, Universidade Técnica de Lisboa (IST), Projet ANR, ANR-11-PRGE-0010,VTG,Verres et vitrocéramiques de chalcogénures en tant que matériaux thermoélectriques pour des applications autour de l'ambiante(2011), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Glass ceramics, Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, engineering.material, 010402 general chemistry, 01 natural sciences, law.invention, Bismuth, Antimony, Thermoelectric manufacturing, law, Seebeck coefficient, Materials Chemistry, Crystallization, Waste heat recovery, Mechanical Engineering, Tetrahedrite, Metallurgy, Metals and Alloys, Low-cost thermoelectric materials, 021001 nanoscience & nanotechnology, Thermoelectric materials, Copper, Tetrahedrites, 0104 chemical sciences, chemistry, Mechanics of Materials, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], engineering, Melt spinning, 0210 nano-technology
Abstract

A Cu 12 Sb 3.6 Bi 0.4 S 10 Se 3 glass was prepared by melt spinning and crystallized by heat treatments at selected temperatures, the total preparation procedure taking less than one day. The sample characterization by powder X-ray diffraction, scanning and transmission electron microscopy complemented with EDS indicate the formation of compact materials, with a tetrahedrite relative weight fraction higher than 90% when treated at temperatures close to the crystallization peaks (∼200° C). Selenium enters the tetrahedrite structure, while bismuth precipitates in submicron and nanosized spherical shape phases depleted in copper and enriched in antimony, sulfur and selenium (when compared with the matrix composition). The characterization of electrical transport properties (electrical resistivity and Seebeck coefficient) indicate a behavior similar to that obtained by other methods on Cu 12 Sb 4 S 13 , with a maximum power factor of ∼400 μW/K 2 m at room temperature.

Published
2016
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15. Nanoscale investigation by TEM and STEM-EELS of the laser induced yellowing

Author

Marie Godet, Mandana Saheb, Nicolas Gauquelin, Judith Monnier, Eric Leroy, Julie Bourgon, Véronique Vergès-Belmin, Christine Andraud, Johan Verbeeck, Laboratoire de recherche des monuments historiques (LRMH), Centre de Recherche sur la Conservation (CRC ), Muséum national d'Histoire naturelle (MNHN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche pour la Conservation des Collections (CRCC), Electron Microscopy for Materials Science - EMAT (Antwerp, Belgium), Universiteit Antwerpen [Antwerpen], Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Universiteit Antwerpen = University of Antwerpen [Antwerpen], Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Ministère de la Culture et de la Communication (MCC), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Nanostructure, General Physics and Astronomy, 02 engineering and technology, Substrate (electronics), 01 natural sciences, law.invention, chemistry.chemical_compound, Crystallinity, Structural Biology, law, 0103 physical sciences, [CHIM]Chemical Sciences, General Materials Science, Irradiation, Magnetite, 010302 applied physics, Physics, Cell Biology, Hematite, 021001 nanoscience & nanotechnology, Laser, Chemistry, Chemical engineering, chemistry, Transmission electron microscopy, visual_art, visual_art.visual_art_medium, 0210 nano-technology
Abstract

International audience; Nd-YAG QS laser cleaning of soiled stone at 1064 nm can sometimes result in a more yellow appearance compared to other cleaning techniques. Especially in France, this yellowing effect is still considered as a major aesthetic issue by the architects and conservators. One explanation states that the yellowing is linked to the formation of iron-rich nanophase(s) through the laser beam interaction with black crusts that would re-deposit on the cleaned substrate after irradiation. To characterize these nanophases, a model crust containing hematite was elaborated and laser irradiated using a Nd-YAG QS laser. The color of the sample shifted instantaneously from red to a bright yellow and numerous particles were ablated in a visible smoke. Transmission electron microscopy (TEM) was used to examine the morphology and the crystallinity of the neo-formed compounds, both on the surface of the samples and in the ablated materials. In addition, an investigation of the chemical and structural properties of the nanophases was conducted by X-ray dispersive energy (EDX) and electron energy loss (EELS) spectroscopies. It was found that both the surface of the sample and the ablated materials are covered by crystallized nano-spheres and nano-residues, all containing iron and oxygen, sometimes along with calcium and sulfur. In particular an interfacial area containing the four elements was evidenced between some nanostructures and the substrate. Magnetite Fe3O4 was also identified at the nanoscale. This study demonstrates that the laser yellowing of a model crust is linked to the presence of iron-rich nanophases including CaxFeySzOδ nanostructures and magnetite Fe3O4 at the surface after irradiation.

Published
2018
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16. Electrochemical oxidation of urea on nickel-rhodium nanoparticles/carbon composites

Author

Stéphane Bastide, Peyman Mirzaei, Claudia Zlotea, Atieh Aghajani, Christine Cachet-Vivier, Arthur Dassy, Diane Muller-Bouvet, Julie Bourgon, Rémi Bensimon, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), and MBA Water Treatment Chemicals Co., Ltd. (MBA)

Subjects
Materials science, Aqueous solution, General Chemical Engineering, chemistry.chemical_element, Nanoparticle, 02 engineering and technology, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Rhodium, Nickel, chemistry.chemical_compound, chemistry, Electrochemistry, Urea, Graphite, Cyclic voltammetry, 0210 nano-technology, Bimetallic strip, ComputingMilieux_MISCELLANEOUS, Nuclear chemistry
Abstract

Ni100-xRhx/C composites consisting in bimetallic nanoparticles (10 wt.%) dispersed in high surface area graphite were synthesized and their electrocatalytic performances for urea oxidation tested in alkaline media by cyclic voltammetry using a cavity microelectrode. The composites are synthesized by impregnation of a graphite powder with an aqueous solution of nickel and rhodium salts, followed by drying and reduction under H2/Ar at 500 °C. TEM observations reveal that the Rh fraction influences the average nanoparticle size which varies from 15 nm for pure Ni to 2 nm for pure Rh. XRD analysis indicates that solid solutions are obtained for all compositions. Ni100-xRhx with up to 30 at.% of rhodium have a higher electrocatalytic activity than pure Ni and their voltammograms exhibit two urea oxidation peaks rather than one, the additional peak being at a potential 50 mV less positive than that of pure nickel. When the rhodium content increases above 30 at.%, the current of urea oxidation decreases and becomes almost zero for pure rhodium. These variations in current as the fraction of rhodium increases are only related to the decrease in nanoparticle size and in nickel content (within a surface layer of ∼1 nm). Hence, there is no synergistic effect between nickel and rhodium for the oxidation of urea in alkaline media.

Published
2018
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17. A (Triphenylphosphine)Silver (I) Complex as a New Performance Additive in Free-Radical Photopolymerization under Air

Author

Nicolas Bogliotti, Arnaud Brosseau, Davy-Louis Versace, Pauline Sautrot-Ba, Pierre-Emmanuel Mazeran, Jacques Lalevée, Julie Bourgon, Fabrice Morlet-Savary, Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM), École normale supérieure - Cachan (ENS Cachan)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Roberval (Roberval), Université de Technologie de Compiègne (UTC), Département de Photochimie Générale (DPG), and Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Polymers and Plastics, General Chemical Engineering, Organic Chemistry, Oxygen inhibition, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Photochemistry, 01 natural sciences, 0104 chemical sciences, chemistry.chemical_compound, Photopolymer, chemistry, Materials Chemistry, [CHIM]Chemical Sciences, Triphenylphosphine, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018
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18. Electrocatalytic Reduction of Nitrate and Nitrite at CuRh Nanoparticles/C Composite Electrodes

Author

Peyman Mirzaei, Julie Bourgon, Christine Cachet-Vivier, Michel Latroche, Stéphane Bastide, Atieh Aghajani, Michel Laurent, Claudia Zlotea, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), MBA Water Treatment Chemicals Co., Ltd. (MBA), Institut des Sciences du Mouvement Etienne Jules Marey (ISM), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, Electrochemistry, 01 natural sciences, Rhodium, Catalysis, Metal, chemistry.chemical_compound, Hydroxylamine, [CHIM]Chemical Sciences, Nitrite, Bimetallic strip, ComputingMilieux_MISCELLANEOUS, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Copper, 0104 chemical sciences, chemistry, visual_art, visual_art.visual_art_medium, 0210 nano-technology
Abstract

Composites consisting of rhodium, copper, and copper-rhodium nanoparticles (2 nm in average diameter) dispersed in a high-surface area graphite powder (~ 10 wt.% of metal) have been synthesized by a wet chemical method. After characterization by ICP-OES and TEM, they have been tested for the electrochemical reduction of nitrates in alkaline media (10−1 mol L−1 KOH) using a cavity microelectrode. It is found that in the 0.02–0.5 V/RHE potential range, bimetallic composites exhibit a much higher electrocatalytic activity than single-metal composites. The peak current describes a volcano plot as a function of the composition, with a maximum for CuRh, which is 7.5 times higher than that obtained with pure rhodium (under identical metal wt.%). This synergistic effect can be rationalized directly from the electrochemical response of pure metals. It is then tentatively attributed to the fact that the first (rate determining) reduction step, corresponding to the formation of nitrites, takes place efficiently in copper-rich areas while the subsequent steps of nitrite reduction in ammonia (via hydroxylamine formation) occur in rhodium-rich areas. For the same mass of rhodium, the electrocatalytic conversion of nitrates to ammonia is 12 times more effective with CuRh than with pure rhodium. With the additional gain in active surface area due to the nanoparticle morphology compared to bulk or thin film forms, these results represent a step-forward in cost reduction of rhodium-based electrocatalysts for the conversion of nitrates to ammonia.

Published
2018
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19. Synthesis of destabilized nanostructured lithium hydride via hydrogenation of lithium electrochemically inserted into graphite

Author

Claudia Zlotea, Liwu Huang, Jean-Pierre Bonnet, Michel Latroche, Matthieu Courty, Julie Bourgon, Luc Aymard, Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Laboratoire réactivité et chimie des solides - UMR CNRS 7314 (LRCS), Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Technologie de Belfort-Montbeliard (UTBM), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire réactivité et chimie des solides (LRCS), Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Thermogravimetric analysis, Materials science, Renewable Energy, Sustainability and the Environment, Thermal decomposition, Intercalation (chemistry), Inorganic chemistry, Energy Engineering and Power Technology, chemistry.chemical_element, Condensed Matter Physics, chemistry.chemical_compound, Hydrogen storage, Fuel Technology, chemistry, Lithium hydride, Desorption, [CHIM]Chemical Sciences, Lithium, Graphite, ComputingMilieux_MISCELLANEOUS
Abstract

Lithium hydride-graphite composite is synthesized through hydrogenation of lithium intercalated graphite obtained by electrochemical insertion. XRD analysis indicates that the initial graphite is transformed into a mixture of LiC6 and LiC12 by the intercalation of 0.84 lithium for six carbons. After 20 h of hydrogenation under 30 bars at 150 °C, these lithium-inserted compounds are completely transformed into a lithium hydride-graphite composite based on the reaction: Li0.84C6 + 0.42H2 → 0.84LiH + 6C. A weak shift and broadening of the (002) reflex of graphite is observed after the formation of LiH, which is attributed to a small increase of the graphite disorder. Thermal gravimetric analysis coupled with Mass Spectrometry (TG-MS) shows that the desorption of this synthesized nano-LiH starts from around 200 °C, which is much lower than the decomposition temperature (900 °C) of pure LiH. It reveals that this new electrochemical synthesis process of LiH-graphite composites enables an interesting destabilization of the Li–H ionic bond due to a good dispersion of highly divided LiH nanoparticles (below 100 nm) in a carbon matrix. The hydrogen storage capacity of this LiH-graphite composite can be increased by subsequent Li insertion/hydrogenation cycles.

Published
2015
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20. First Evidence of Rh Nano-Hydride Formation at Low Pressure

Author

Stéphane Bastide, Michel Latroche, Claudia Zlotea, Mariem Msakni, Yassine Oumellal, Christine Cachet-Vivier, Julie Bourgon, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), and Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Hydrogen, Chemistry, Hydride, Mechanical Engineering, Inorganic chemistry, chemistry.chemical_element, Nanoparticle, Bioengineering, General Chemistry, Thermal treatment, Condensed Matter Physics, Metal, Chemical engineering, 13. Climate action, Phase (matter), visual_art, visual_art.visual_art_medium, [CHIM]Chemical Sciences, General Materials Science, Thermal analysis, ComputingMilieux_MISCELLANEOUS, Solid solution
Abstract

Rh-based nanoparticles supported on a porous carbon host were prepared with tunable average sizes ranging from 1.3 to 3.0 nm. Depending on the vacuum or hydrogen environment during thermal treatment, either Rh metal or hydride is formed at nanoscale, respectively. In contrast to bulk Rh that can form a hydride phase under 4 GPa pressure, the metallic Rh nanoparticles (∼2.3 nm) absorb hydrogen and form a hydride phase at pressure below 0.1 MPa, as evidenced by the presence of a plateau pressure in the pressure-composition isotherm curves at room temperature. Larger metal nanoparticles (∼3.0 nm) form only a solid solution with hydrogen under similar conditions. This suggests a nanoscale effect that drastically changes the Rh-H thermodynamics. The nanosized Rh hydride phase is stable at room temperature and only desorbs hydrogen above 175 °C. Within the present hydride particle size range (1.3-2.3 nm), the hydrogen desorption is size-dependent, as proven by different thermal analysis techniques.

Published
2015
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21. Wetting by liquid sodium and fracture path analysis of sodium induced embrittlement of 304L stainless steel

Author

Julie Bourgon, Bassem Barkia, Jean Louis Courouau, Thierry Auger, Laboratoire de mécanique des sols, structures et matériaux (MSSMat), CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de mécanique des solides (LMS), École polytechnique (X)-MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Procédés et Ingénierie en Mécanique et Matériaux (PIMM), Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), École polytechnique (X)-Mines Paris - PSL (École nationale supérieure des mines de Paris), Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Centre National de la Recherche Scientifique (CNRS)-Arts et Métiers Sciences et Technologies, and HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)

Subjects
010302 applied physics, Austenite, Materials science, Mechanical Engineering, Sodium, chemistry.chemical_element, 02 engineering and technology, Intergranular corrosion, Sciences de l'ingénieur, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Corrosion, [SPI]Engineering Sciences [physics], chemistry, Mechanics of Materials, Liquid metal embrittlement, 0103 physical sciences, General Materials Science, Wetting, Composite material, 0210 nano-technology, Embrittlement, Hydrogen embrittlement
Abstract

International audience; The wettability of the 304L steel is an important parameter in Liquid Metal Embrittlement studies. Empirically, it is found to be greatly enhanced by pre-exposure to oxygenated liquid sodium. The corrosion interface formed during exposure to sodium has been analyzed at the nanoscale by transmission electron microscopy using the focused ion beam sampling. A thin layer of sodium chromite (Na xCrO2 with x ≤ 1) is detected at the interface validating wetting on an oxide mechanism for the enhanced wetting after pre-exposure. Fracture micromechanisms and the crack path of liquid sodium-embrittled austenitic steel 304L at 573 K have been investigated down to the nanoscale. High-resolution orientation mapping analyses immediately below the fracture surface show that abundant martensitic transformations (γ → α) and twinning occur during deformation of austenite. The preferential crack path is intergranular along the newly formed γ/γ interfaces. It is concluded that these transformations play a major role in the fracture process.

Published
2018
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22. Investigation of the local structure of nanosized rhodium hydride

Author

Laurent Piccolo, Lucie Blondeau, Julie Bourgon, Claudia Zlotea, Franck Morfin, Abdelmalek Malouche, Karine Provost, IRCELYON-Ingéniérie, du matériau au réacteur (ING), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and IRCELYON-Catalyse Hétérogène pour la Transition Energétique (CATREN)

Subjects
Phase transition, Materials science, Absorption spectroscopy, Hydrogen, Hydride, chemistry.chemical_element, 02 engineering and technology, [CHIM.CATA]Chemical Sciences/Catalysis, Atmospheric temperature range, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, [SDE.ES]Environmental Sciences/Environmental and Society, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Biomaterials, Colloid and Surface Chemistry, chemistry, Desorption, Physical chemistry, Thermal stability, 0210 nano-technology, Spectroscopy
Abstract

The local structure and the thermal stability of small and well-dispersed RhHx nanoparticles (average size of 1.4 nm) were studied by in situ X-ray Absorption Spectroscopy. The RhHx nanoparticles are stable at room temperature and undergo a structural transition from hydride (fcc) to metal phase (fcc) with a shrinking of the lattice volume due to the desorption of hydrogen. This phase transition occurs in the temperature range of 150–180 °C, in good agreement with the results from thermo-desorption spectroscopy. Above 180 °C, the desorbed nanoparticles undertake important coalescence. In situ transmission electron microscopy performed up to 300 °C proves that this process cannot be only thermal, thus it may be ascribed to a X-ray beam effect.

Published
2018
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23. Impact of coherent and incoherent twin boundaries on the microhardness of annealed nanocrystalline Ni–W alloys

Author

N. Shakibi Nia, C. Savall, Julie Bourgon, Egle Conforto, Xavier Feaugas, M. Lagarde, Jordi Creus, Laboratoire des Sciences de l'Ingénieur pour l'Environnement - UMR 7356 (LaSIE), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Microstructural evolution, Materials science, Annealing (metallurgy), Metallurgy, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Indentation hardness, Nanocrystalline material, Nanomaterials, [SPI.MAT]Engineering Sciences [physics]/Materials, Grain growth, 0103 physical sciences, Forensic engineering, Grain boundary, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

The microstructural evolution of nanocrystalline Ni–W alloys with annealing temperature and more specifically grain boundary (GB) character is investigated through several techniques and correlated...

Published
2017
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24. Annealing Effects in Nanograined Al-Cu-Mg Alloy Processed by Equal Channel Angular Pressing

Author

Nabil Njah, Yannick Champion, Jean Philippe Couzine, Julie Bourgon, Hassan Houcin Ktari, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Science et Ingénierie des Matériaux et Procédés (SIMaP ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Sfax - University of Sfax, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Science et Ingénierie des Matériaux et Procédés (SIMaP), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)

Subjects
010302 applied physics, Pressing, Materials science, Annealing (metallurgy), Mechanical Engineering, Metallurgy, Alloy, 02 engineering and technology, Calorimetry, [CHIM.MATE]Chemical Sciences/Material chemistry, engineering.material, 021001 nanoscience & nanotechnology, 01 natural sciences, Mechanics of Materials, visual_art, 0103 physical sciences, engineering, Aluminium alloy, visual_art.visual_art_medium, General Materials Science, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

The microstructure and mechanical properties were investigated in an industrial Al-Cu-Mg alloy processed by Equal Channel Angular Pressing ECAP and heating. The die used is formed by two channels intersecting at an angle 90°. Transmission Electron Microscopy (TEM) and orientation (ASTAR) imaging were used in addition to hardness measurements. After heating, a sub-micron grain size is retained. In addition, a further hardening is observed due to secondary precipitation. Differential Scanning Calorimetry (DSC) showed that the activation energy of θ’ precipitation is strongly lowered after ECAP.

Published
2017
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25. Deformation and fracture behavior of new strain-transformable titanium alloys: a multi-scale investigation

Author

Frédéric Prima, Chloé Varenne, Anne-Françoise Gourgues-Lorenzon, Jacques Besson, Julie Bourgon, Cédrik Brozek, Centre des Matériaux (MAT), MINES ParisTech - École nationale supérieure des mines de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Scale (ratio), Strain (chemistry), technology, industry, and agriculture, 030232 urology & nephrology, Titanium alloy, equipment and supplies, Engineering (General). Civil engineering (General), [SPI.MAT]Engineering Sciences [physics]/Materials, 03 medical and health sciences, 0302 clinical medicine, 030220 oncology & carcinogenesis, Fracture (geology), TA1-2040, Deformation (engineering), Composite material, ComputingMilieux_MISCELLANEOUS
Abstract

Titanium alloys possessing Twinning and Transformation Induced Plasticity effects show promising mechanical properties, particularly high ductility, hardenability, impact and fracture toughness. This work focuses on a strain-transformable, coarse-grained β-Ti-Cr-Sn alloy displaying TWIP effect. To account for the enhanced properties of this alloy, compared to more conventional β-Ti alloys, fracture and deformation features were correlated at different scales. Examinations evidenced a major role of twinning and, more generally, of plasticity-induced phenomena in the ductile fracture process. The resistance of this alloy to plastic deformation (work-hardening), and to crack initiation and propagation is interpreted in view of the progressive, multiscale twinning mechanisms that occur up to the very final stages of fracture.

Published
2020
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26. Laser yellowing effect: study of the nanophases created by laser irradiation of synthetic black crusts using transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) spectroscopy

Author

Christine Andraud, Véronique Vergès-Belmin, Eric Leroy, Julie Bourgon, Mandana Saheb, Judith Monnier, Marie Godet, and Laurent Binet

Subjects
Materials science, law, Transmission electron microscopy, Irradiation, Effect study, Electron paramagnetic resonance, Laser, Photochemistry, law.invention
Published
2017
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28. On the implication of solute contents and grain boundaries on the Hall-Petch relationship of nanocrystalline Ni-W alloys

Author

C. Savall, N. Shakibi Nia, Jordi Creus, Patrick Girault, Arnaud Metsue, Xavier Feaugas, S. Cohendoz, Julie Bourgon, Laboratoire des Sciences de l'Ingénieur pour l'Environnement - UMR 7356 (LaSIE), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)

Subjects
Materials science, Thermodynamics, chemistry.chemical_element, 02 engineering and technology, Flow stress, Tungsten, 01 natural sciences, 0103 physical sciences, Grain boundary diffusion coefficient, General Materials Science, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], ComputingMilieux_MISCELLANEOUS, Grain boundary strengthening, 010302 applied physics, [PHYS]Physics [physics], Mechanical Engineering, Metallurgy, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Grain size, Nanocrystalline material, chemistry, Mechanics of Materials, Hardening (metallurgy), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Grain boundary, 0210 nano-technology
Abstract

Nano-crystalline nickel-tungsten alloys are investigated in order to provide evidence of the contribution of the solute content (light elements and tungsten) and grain-boundaries on hardness. For this purpose, Ni-W alloys were elaborated by electrodeposition in an additive free citrate ammonium bath. The variation of electrodeposition conditions leads to W contents up to 18 at%, with a broad range of grain sizes (5–650 nm). The incorporation of light elements (H, O, C, N) depends on the deposition applied conditions and a progressive modification of the texture is observed with the following sequence: {110}, NT (Non-Textured) and {111} textures. We show that the Hall-Petch relationship for these alloys is influenced by the presence of light elements, the nature of the crystallographic texture and the grain boundaries character. The dependence of grain size on flow stress is a direct consequence of the solute content (solute strengthening) and the evolution of the internal stresses with grain size. To explain the experimental data, two competing physical mechanisms are suggested: grain boundary shearing and dislocation emission at grain boundary, which are affected by the nature of the grain boundary and the solute content.

Published
2016
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29. Influence of High-Pressure Torsion on the Microstructure and the Hardness of a Ti-Rich High-Entropy Alloy

Author

Jenő Gubicza, Anita Heczel, Terence G. Langdon, Ivan Guillot, Guy Dirras, Lola Lilensten, Yi Huang, Jean Philippe Couzine, Julie Bourgon, Loïc Perrière, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mathématiques d'Orsay (LM-Orsay), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), University of Southampton, and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Phase transition, Materials science, Mechanical Engineering, Metallurgy, Alloy, Torsion (mechanics), 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, engineering.material, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Microstructure, 01 natural sciences, Grain size, 0104 chemical sciences, Mechanics of Materials, Transmission electron microscopy, Martensite, engineering, General Materials Science, Severe plastic deformation, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

High-Pressure Torsion (HPT) is one of the most effective severe plastic deformation techniques in grain refinement. The goal of this study was to investigate the influence of HPT on the microstructure and hardness of a Ti-rich High-Entropy Alloy (HEA). The evolution of the grain size due to 1 turn of HPT was studied by transmission electron microscopy. Besides the refinement of the microstructure, a phase transition also occurred during HPT, as revealed by X-ray diffraction. The initial bcc structure transformed into a martensitic phase throughout the material. The features of this phase transformation were studied on a sample compressed to low strain values. The hardness as a function of the distance from the center in the HPT-processed disk was measured and correlated to the microstructure.

Published
2016
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30. Design and tensile properties of a bcc Ti-rich high-entropy alloy with transformation-induced plasticity

Author

Frédéric Prima, Julie Bourgon, Ivan Guillot, Loïc Perrière, Lola Lilensten, Guy Dirras, Jean-Philippe Couzinié, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Laboratoire de Physico-Chimie des Surfaces (LPCS), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Alloy, 02 engineering and technology, Work hardening, engineering.material, Plasticity, mechanical properties, 01 natural sciences, martensitic phase transformation, titanium alloys, 0103 physical sciences, lcsh:TA401-492, General Materials Science, High-entropy alloy, Ductility, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, work hardening, Metallurgy, Titanium alloy, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Microstructure, Martensite, engineering, lcsh:Materials of engineering and construction. Mechanics of materials, Deformation (engineering), 0210 nano-technology
Abstract

A new bcc Ti-rich high-entropy alloy (HEA) of composition Ti35Zr27.5Hf27.5Nb5Ta5 was designed using the ‘d-electron alloy design’ approach. The tensile behavior displays a marked transformation-induced plasticity effect resulting in a high normalized work-hardening rate of 0.103 without loss of ductility when compared to the reference composition Ti20Zr20Hf20Nb20Ta20. In this paper, a detailed microstructural analysis was performed to understand the deformation process, revealing architectural-type microstructures and a high volume fraction (65%) of internally twinned stress-induced martensite α″ after mechanical testing. This study opens the way to mechanical properties optimization and enhancement of titanium-based HEAs by combining multiple alloying designs. IMPACT STATEMENT For the first time, proof is given that transformation-induced plasticity was triggered in a bcc refractory high-entropy alloy, leading to a twofold increase in the normalized work-hardening rate.

Published
2016
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31. Synthesis and stability of Pd–Rh nanoalloys with fully tunable particle size and composition

Author

Jean-Marc Le Meins, Julie Bourgon, Jean-Marc Joubert, Yassine Oumellal, Camelia Matei Ghimbeu, Claudia Zlotea, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace, Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Strasbourg (UNISTRA)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Université de Strasbourg (UNISTRA), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Chimie métallurgique des terres rares (CMTR), Centre National de la Recherche Scientifique (CNRS), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Laboratoire de Matériaux Minéraux (LMM), and Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Ecole Nationale Supérieure de Chimie de Mulhouse-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Spinodal decomposition, Analytical chemistry, Nanotechnology, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Particle-size distribution, Melting point, Particle, [CHIM]Chemical Sciences, General Materials Science, Particle size, Physical and Theoretical Chemistry, 0210 nano-technology, Incipient wetness impregnation, ComputingMilieux_MISCELLANEOUS, Phase diagram, Solid solution
Abstract

Bulk immiscible Pd–Rh nanoalloys supported on carbon are easily formed with tunable compositions and average particle sizes by two different methods: an indirect method (incipient wetness impregnation followed by reduction under H 2 at 300 and 500 °C) along with a direct one (one-pot route heat treated at 600 °C under Ar). The main advantage of our synthetic methods is the easy implementation as well as the formation of nanoalloys with well controlled composition and particle size distribution. For the indirect route at 300 °C, the nanoalloys have an average particle size of around 2 nm, irrespective of the composition. However, the average particle sizes show a strong composition dependence for higher synthetic temperatures: it decreases from around 6 to 2 nm with increasing Rh content for the indirect method at 500 °C, whereas it increases from around 6 to 10 nm for the direct method at 600 °C with increasing Rh content. Moreover, our calculation of the phase diagram taking into account the size effect within the Nano-Calphad approach confirms that these nanoalloys are non-equilibrium phases. The change of the binary phase diagram due to the size effect (decrease of the melting points of pure elements, reduction of the critical temperature along with modifications in the solubility limits of the miscibility gap) cannot account for the formation of Pd–Rh solid solutions at nanoscale.

Published
2016
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32. Modified strain rate regime in ultrafine grained copper with silver micro-alloying

Author

Xavier Sauvage, Julie Bourgon, Yannick Champion, Science et Ingénierie des Matériaux et Procédés (SIMaP ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Groupe de physique des matériaux (GPM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Silver, Oxide, Sintering, Spark plasma sintering, chemistry.chemical_element, 02 engineering and technology, Micro-alloying, 01 natural sciences, Stress (mechanics), chemistry.chemical_compound, 0103 physical sciences, General Materials Science, 010302 applied physics, Mechanical Engineering, Metallurgy, Ultrafine grained, Strain rate, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Copper, Grain size, chemistry, Mechanics of Materials, Grain boundary, Strength, 0210 nano-technology
Abstract

Ultrafine grained (UFG) copper with an average grain size of 115 nm was micro-alloyed with silver (UFG CuAg) to analyze its effect on strain rate sensitivity. The materials were prepared by sintering Ag microalloyed-Cu ultrafine powder, using the spark plasma sintering (SPS) technique and after H2 pre-annealing for oxide reduction. Mechanical tests show that UFG CuAg follows the law of behavior established for UFG Cu: m ≈ B ( 1 − σ 0 / σ ) , relating the strain rate sensitivity m and the applied stress, σ . In this relation, σ 0 is a threshold grain size dependent stress and B is characterizing the grain boundaries diffusion properties. Main difference compared to pure UFG copper is a large value of the parameter B for UFG CuAg, indicating a dominant role of the grain boundaries structure and chemistry on the rheology of UFG metals.

Published
2016
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33. New structure in refractory high-entropy alloys

Author

Loïc Perrière, Lola Lilensten, Ivan Guillot, Jean-Philippe Couzinié, Julie Bourgon, and Nicolas Emery

Subjects
Materials science, Rietveld refinement, Mechanical Engineering, High entropy alloys, Alloy, engineering.material, Condensed Matter Physics, Microstructure, Crystallography, Mechanics of Materials, Martensite, Stress relaxation, engineering, General Materials Science, Orthorhombic crystal system, Composite material, Solid solution
Abstract

The microstructure of a new refractory high-entropy alloy of composition close to Ti 35 Zr 27.5 Hf 27.5 Nb 5 Ta 5 prepared by arc melting and induction techniques was investigated using X-Ray diffraction (XRD) and transmission electron microscopy (TEM). This alloy presents optimal empirical parameters for the formation of a solid solution phase. The as-cast material displays a density of 8480 kg m −3 and a Vickers microhardness close to 2400 MPa. While the Rietveld refinement of XRD data indicates an orthorhombic (martensite) α׳׳-type structure for the bulk alloy, TEM observations prove that the alloy exhibits a twinned hexagonal structure as thin foil. An orthorhombic–hexagonal transformation by stress relaxation during TEM sample preparation is discussed.

Published
2014
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34. Orientation imaging- ASTAR investigation of the grain and precipitate morphology in Al–Cu–Mg alloy processed by Equal Channel Angular Pressing

Author

Yannick Champion, Nabil Njah, Jean-Philippe Couzinié, Hassan Houcin Ktari, Julie Bourgon, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Science et Ingénierie des Matériaux et Procédés (SIMaP), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Institut National Polytechnique de Grenoble (INPG), Université de Sfax - University of Sfax, ICMPE - Institut de Chimie et des Matériaux Paris-Est, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)

Subjects
Pressing, business.product_category, Materials science, Morphology (linguistics), Mechanical Engineering, Alloy, Metallurgy, Metals and Alloys, [CHIM.MATE]Chemical Sciences/Material chemistry, Strain rate, engineering.material, Compression (physics), Grain size, Mechanics of Materials, Materials Chemistry, engineering, Die (manufacturing), Grain boundary, business, ComputingMilieux_MISCELLANEOUS
Abstract

Multiphase alloys are usually serious candidates for structural applications. Their mechanical properties depend on the precipitate distribution. We have studied the effects of Equal Channel Angular Pressing (ECAP) on the morphology of grains and precipitates in an Al–Cu–Mg alloy. Precipitates are mainly incoherent θ-Al 2 Cu and S–Al 2 CuMg. ECAP was performed using a die with an angle 90° up to three passes. TEM shows that high density of dislocations is created for the two first passages then for N = 3, new grains 200 nm in size are clearly observed. Orientation imaging (ASTAR) shows that many precipitates are crushed by ECAP and that the new grains are randomly oriented. The new high angle grain boundaries are pinned by precipitates and the grain size seems to be limited by the distance between precipitates. From strain rate jump experiments in compression, a reduction of the activation volume V* was observed after ECAP.

Published
2015
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35. Formation of annealing twins during primary recrystallization of two low stacking fault energy Ni-based alloys

Author

Wei Wang, Sylvie Lartigue-Korinek, Julie Bourgon, Anne-Laure Helbert, Thierry Baudin, François Brisset, State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering [Nanjing] (HYDRO-LAB), Hohai University, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Laboratoire de Physico-Chimie de l'Etat Solide (CHIMSOL), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Twinning, Nickel alloy, Annealing (metallurgy), EBSD, chemistry.chemical_element, 02 engineering and technology, Stacking-fault energy, General Materials Science, ComputingMilieux_MISCELLANEOUS, 020502 materials, Mechanical Engineering, Metallurgy, technology, industry, and agriculture, Recrystallization (metallurgy), [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Nickel, 0205 materials engineering, chemistry, Mechanics of Materials, Transmission electron microscopy, Solid mechanics, Stored energy, TEM, Partial dislocations, 0210 nano-technology, Crystal twinning
Abstract

International audience; First stages of recrystallization are analyzed in low stacking fault energy nickel alloys cold rolled and subsequently annealed at 700°C for 6 minutes. These alloys are envisaged as candidate materials for the heat exchanger of VHTR (Very High Temperature Reactor) that works at 1000°C. First recrystallized grains show evidence of extensive twinning that is studied by Transmission Electron Microscopy. Specific twinning features such as five-fold twin and microtwins bordered by partial dislocations are revealed. Twin density increases with increasing amounts of prior deformation before annealing. The local crystal orientations are determined at a nanometer scale. It is shown directly that when twinning occurs, the recrystallized area beyond the twin has a lower stored deformation energy. Thus recrystallization and the associate twinning induce a decrease in the total stored deformation energy.

Published
2015
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36. In situ production of visible light absorbing Ti-based nanoparticles in solution and in a photopolymerizable cationic matrix

Author

D.L. Versace, Julie Bourgon, Jacques Lalevée, Romain Poupart, Jean Pierre Fouassier, Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Paris-Est Créteil Val-de-Marne - Faculté de médecine (UPEC Médecine), and Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)

Subjects
Materials science, Nanoparticle, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, Catalysis, Matrix (chemical analysis), chemistry.chemical_compound, Materials Chemistry, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS, Metals and Alloys, Cationic polymerization, General Chemistry, 021001 nanoscience & nanotechnology, Toluene, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Solvent, chemistry, Ceramics and Composites, 0210 nano-technology, Derivative (chemistry), Visible spectrum, Titanium
Abstract

A novel straightforward approach has been proposed to generate in situ, under light activation and in aerated media, visible-light absorbing and well-defined titanium-based nanoparticles (NPs) in solution and in an epoxide matrix using titanium derivative complexes/iodonium salt photoinitiating systems. The nature of the solvent and oxygen plays a decisive role, and two mechanisms involved in these syntheses are operative, i.e. a photofragmentation/addition process (in toluene and isopropanol) and a photoinduced sol–gel reaction (in isopropanol).

Published
2015
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37. Identification of a new pseudo-binary hydroxide during calendar corrosion of (La, Mg)2Ni7-type hydrogen storage alloys for Nickel-Metal Hydride batteries

Author

H. Chen, Michel Latroche, Julie Bourgon, Suzanne Joiret, Judith Monnier, Institut de Chimie et des Matériaux Paris-Est (ICMPE), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interfaces et Systèmes Electrochimiques (LISE), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Inorganic chemistry, Energy Engineering and Power Technology, chemistry.chemical_element, Raman micro spectroscopy, Corrosion, Metal, Hydrogen storage, chemistry.chemical_compound, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Electrode material, Renewable Energy, Sustainability and the Environment, Hydride, Nanoporous, Metallurgy, Ni-MH batteries, Combination of techniques, Nickel, chemistry, visual_art, visual_art.visual_art_medium, TEM, Hydroxide, [CHIM.OTHE]Chemical Sciences/Other
Abstract

International audience; To improve the performances of Nickel-Metal Hydride batteries, an important step is the understanding of the corrosion processes that take place in the electrode material. In particular, the present study focuses for the first time on the model (La, Mg)2Ni7 system. The calendar corrosion in 8.7 M KOH medium was investigated from 6 h to 16 weeks immersion. By a unique combination of structural and elemental characterisations, the corrosion products are evidenced in those systems. In particular, we demonstrate that Ni and Mg combine in a pseudo-binary hydroxide Mg1−xNix(OH)2 whereas La corrodes into nanoporous La(OH)3 needles with inner hollow nanochannels.

Published
2014
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38. Surface-dependent oxidation of H 2 on CeO 2 surfaces

Author

V. Chiodo, Armelle Ringuedé, Frédéric Labat, Jean-Philippe Couzinié, S. Freni, Giuseppe Bonura, Julie Bourgon, Carlo Adamo, Thomas Désaunay, Michel Cassir, Laboratoire d'Electrochimie, Chimie des Interfaces et Modélisation pour l'Energie (LECIME - UMR 7575) (LECIME), Institut de Chimie du CNRS (INC)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche de Chimie Paris (IRCP), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC)

Subjects
Surface (mathematics), Order of reaction, Hydrogen, Chemistry, Nanoparticle, chemistry.chemical_element, Nanotechnology, 02 engineering and technology, [CHIM.CATA]Chemical Sciences/Catalysis, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Catalysis, 0104 chemical sciences, Chemical engineering, Transmission electron microscopy, [CHIM]Chemical Sciences, Nanorod, Physical and Theoretical Chemistry, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, Surface states
Abstract

In this study, ceria nanoparticles with well-defined surface states were synthesized in order to enable the study of different ceria surfaces, independently. Ceria nanocubes were shown to expose only (1 0 0) surfaces, ceria nanooctahedra only (1 1 1) surfaces, and ceria nanorods are more complex, with at least 50% of (1 1 0) surfaces, as shown by high-resolution transmission electron microscopy. Temperature-programmed reduction (TPR) by hydrogen performed on these powders shows the following order of reaction temperatures: cubes < rods < octahe dra. Moreover, activation energies associated with the first surface reduction in each sample show a similar trend. Ceria (1 0 0) surface is the most reactive toward hydrogen oxidation, while (1 1 1) surface is the less reactive, and (1 1 0) surface has likely an intermediate behavior. These results confirm that hydrogen oxidation is highly surface-d.

Published
2013
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