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39documents trouvés

17467
19/12/2017

Alickia: Aluminothermite Initiation and Combustion Kinetic Algorithm. Notice d'utilisation

V.BAIJOT, M.DJAFARI ROUHANI, C.ROSSI, A.ESTEVE

NEO

Rapport LAAS N°17467, Décembre 2017, 24p.

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141862
17466
19/12/2017

Alickia: Aluminothermite Initiation and Combustion Kinetic Algorithm. Guide de démarrage rapide

V.BAIJOT, M.DJAFARI ROUHANI, C.ROSSI, A.ESTEVE

NEO

Rapport LAAS N°17466, Décembre 2017, 4p.

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141861
17137
11/12/2017

Role of Trimethylaluminum (TMA) in low temperature atomic layer deposition of silicon nitride

A.DANGERFIELD, C.E.NANAYAKKARA, A.MALLIKARJUNAN, X.LEI, R.M.PEARLSTEIN, A.DERECSKEI-KOVACS, J.CURE, A.ESTEVE, Y.J.CHABAL

University of Texas, Versum Materials Inc, NEO

Revue Scientifique : Chemistry of Materials, Vol.29, N°14, pp.6022-6029, Décembre 2017, DOI: 10.1021/acs.chemmater.7b01816 , N° 17137

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Abstract

Aminosilanes are attractive precursors for atomic layer deposition of silicon oxides and nitrides because they are halide-free and more reactive than chlorosilanes. However, the deposition of silicon nitride on oxide substrates still requires relatively high temperatures. We show here that for a process involving disec-butylaminosilane and hydrazine, the insertion of Al from trimethyl aluminum allows the deposition of silicon nitride films at relatively low temperatures (250 °C). First-principles calculations reveal that the presence of Al increases the binding of molecular hydrazine, thereby effectively enhancing the reactivity of hydrazine with the silicon precursor during the atomic layer deposition process, which leads to nitrogen incorporation into silicon. However, the range of this enhancement is limited to ∼1 nm, requiring additional trimethylaluminum exposures to continue the Si3N4 deposition.

141737
17156
01/12/2017

Ultra-rapid and fully integrated active pyrotechnic safety switches integrating nanothermites

A.NICOLLET, S.CHARLOT, V.BAIJOT, A.ESTEVE, C.ROSSI

NEO, TEAM

Manifestation avec acte : MRS Fall Meeting 2017 du 26 novembre au 01 décembre 2017, Boston (USA), Décembre 2017, 1p. , N° 17156

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141633
17459
22/11/2017

Modélisation et simulation multi-niveaux de la combustion d’une thermite composée de nanoparticules Al/CuO : des phénomènes microscopiques à la simulation du système en combustion

V.BAIJOT

NEO

Doctorat : Université de Toulouse III - Paul Sabatier, 22 Novembre 2017, 175p., Président: G.DAMAMME, Rapporteurs: L.CATOIRE, Examinateurs: E.LAFONTAINE, V.COULET, Directeurs de thèse: A.ESTEVE, C.ROSSI , N° 17459

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Abstract

This thesis work deals with understanding and modeling the combustion of a mixture of nanoparticle made of aluminum and metal oxide. In this context, we developed a kinetic model, based on multiple elementary phenomena : diffusion, reaction, condensation, vaporization and decomposition. We showed that this model allows to predict the evolution of the pressure generated during the combustion as a function of multiple parameters : packing, proportion of aluminum and metal oxide, and particle sizes. Finally, this model have been coupled with a description of the thermal transport, in order to study the effect of heat losses in a combustion chamber.

Résumé

Ce travail de thèse porte sur la compréhension et la modélisation de la combustion de mélange de nanoparticules composée d’aluminium et d’oxydes métallique. Dans ce cadre, nous avons développé un modèle cinétique, reposant sur un ensemble de phénomènes élémentaires : diffusion, réactions, condensations, évaporations et décompositions. Nous avons montré que ce modèle permet de prédire l’évolution de la pression généré en fonction de nombreux paramètres : la compaction, la proportion d’aluminium et d’oxyde métallique et la taille des particules du mélange. Enfin, ce modèle a été couplé à une description des transferts thermiques lors de la combustion, afin d’étudier l’effet des pertes thermiques dans une chambre de combustion.

Mots-Clés / Keywords
Thermite; Nanoparticules; Modélisation multi-échelles; Combustion; Cinétique chimique; Al/CuO;

141815
17390
23/10/2017

A diffusion–reaction scheme for modeling ignition and self-propagating reactions in Al/CuO multilayered thin films

G.LAHINER, A.NICOLLET, JA.ZAPATA CORREA, L.MARIN MERCADO, N.RICHARD, M.DJAFARI ROUHANI, C.ROSSI, A.ESTEVE

NEO, CEA-DAM

Revue Scientifique : Journal of Applied Physics, Vol.122, N°15, 155105p., Octobre 2017 , N° 17390

Lien : https://hal.laas.fr/hal-01620567

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Abstract

Thermite multilayered films have the potential to be used as local high intensity heat sources for a variety of applications. Improving the ability of researchers to more rapidly develop Micro Electro Mechanical Systems devices based on thermite multilayer films requires predictive modeling in which an understanding of the relationship between the properties (ignition and flame propagation), the multilayer structure and composition (bilayer thicknesses, ratio of reactants, and nature of interfaces), and aspects related to integration (substrate conductivity and ignition apparatus) is achieved. Assembling all these aspects, this work proposes an original 2D diffusion-reaction modeling framework to predict the ignition threshold and reaction dynamics of Al/CuO multilayered thin films. This model takes into consideration that CuO first decomposes into Cu2O, and then, released oxygen diffuses across the Cu2O and Al2O3 layers before reacting with pure Al to form Al2O3. This model is experimentally validated from ignition and flame velocity data acquired on Al/CuO multilayers deposited on a Kapton layer. This paper discusses, for the first time, the importance of determining the ceiling temperature above which the multilayers disintegrate, possibly before their complete combustion, thus severely impacting the reaction front velocity and energy release. This work provides a set of heating surface areas to obtain the best ignition conditions, i.e., with minimal ignition power, as a function of the substrate type.

141327
17376
01/09/2017

DNA grafting and arrangement on oxide surfaces for self-assembly of Al and CuO nanoparticles

T.CALAIS, D.BOURRIER, A.BANCAUD, Y.J.CHABAL, A.ESTEVE, C.ROSSI

NEO, TEAM, MILE, University of Texas

Revue Scientifique : Langmuir, Septembre 2017, DOI 10.1021/acs.langmuir.7b02159 , N° 17376

Lien : https://hal.laas.fr/hal-01613194

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Abstract

DNA-directed assembly of nano-objects as a means to manufacture advanced nanomaterial architectures has been the subject of many studies. However, most applications have dealt with noble metals as there are fundamental difficulties to work with other materials. In this work, we propose a generic and systematic approach for functionalizing and characterizing oxide surfaces with single-stranded DNA oligonucleotides. This protocol is applied to aluminum and copper oxide nanoparticles due to their great interest for the fabrication of highly energetic heterogeneous nanocomposites. The surface densities of streptavidin and biotinylated DNA oligonucleotides are precisely quantified combining atomic absorption spectroscopy with conventional dynamic light scattering and fluorimetry, and maximized to provide a basis for understanding the grafting mechanism. First, the streptavidin coverage is consistently below 20% of the total surface for both nanoparticles. Second, direct and unspecific grafting of DNA single strands onto Al and CuO nanoparticles largely dominates the overall functionalization process:

141261
17369
01/09/2017

Performance enhancement via incorporation of ZnO nanolayers in energetic Al/CuO multilayers

L.MARIN MERCADO, Y.GAO, M.VALLET, I.ABDALLAH, B.WAROT-FONROSE, C.TENAILLEAU, A.LUCERO, J.KIM, A.ESTEVE, Y.J.CHABAL, C.ROSSI

NEO, CEMES/CNRS, CIRIMAT, University of Texas

Revue Scientifique : Langmuir, 8p., Septembre 2017, DOI: 10.1021/acs.langmuir.7b02964 , N° 17369

Lien : https://hal.archives-ouvertes.fr/hal-01613523

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Abstract

Al/CuO energetic structure are attractive materials due to their high thermal output and propensity to produce gas. They are widely used to bond components or as next generation of MEMS igniters. In such systems, the reaction process is largely dominated by the outward migration of oxygen atoms from the CuO matrix toward the aluminum layers, and many recent studies have already demonstrated that the interfacial nanolayer between the two reactive layers plays a major role in the material properties. Here we demonstrate that the ALD deposition of a thin ZnO layer on the CuO prior to Al deposition (by sputtering) leads to a substantial increase in the efficiency of the overall reaction. The CuO/ZnO/Al foils generate 98% of their theoretical enthalpy within a single reaction at 900 °C, whereas conventional ZnO-free CuO/Al foils produce only 78% of their theoretical enthalpy, distributed over two distinct reaction steps at 550 °C and 850 °C. Combining high-resolution transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry, we characterized the successive formation of a thin zinc aluminate (ZnAl2O4) and zinc oxide interfacial layers, which act as an effective barrier layer against oxygen diffusion at low temperature.

141239
17098
09/06/2017

Basic mechanisms of Al interaction with the ZnO surface

Y.GAO, L.MARIN MERCADO, E.C.MATTSON, J.CURE, C.E.NANAYAKKARA, J.F.VEYAN, A.LUCERO, J.KIM, C.ROSSI, A.ESTEVE, Y.J.CHABAL

University of Texas, NEO

Revue Scientifique : Journal of Physical Chemistry C, Vol.121, N°23, pp.12780-12788, Juin 2017, DOI: 10.1021/acs.jpcc.7b02661 , N° 17098

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Abstract

Deposition of Al on ZnO is used for a number of electronic and catalytic devices as well as for nanoenergetic materials. The interface structure and chemical composition often control the performance of devices. In this study, in situ infrared spectroscopy, X-ray photoemission spectroscopy, and low energy ion scattering are combined to investigate the initial stage of interface formation between Al and ZnO. We find that (a) the interface is highly inhomogeneous with discontinuous Al patches, leaving ∼10% of the ZnO surface uncovered even after deposition of an equivalent of 11 nm-thick Al film; (b) upon Al deposition, Al reduces ZnO by forming Al2O3 and releasing Zn to the surface, and this process continues as more Al is deposited; (c) the reduced surface Zn atoms readily desorb at 150 °C; and (d) at higher temperature (>600 °C) all Al is oxidized as a result of mass transport. Deposition of a thin Al2O3 layer on ZnO prior to Al deposition effectively prevents Al penetration and Zn release, requiring higher temperatures to oxidize Al.

139893
16410
01/06/2017

A multi-phase micro-kinetic model for simulating aluminium based thermite reaction

V.BAIJOT, M.DJAFARI ROUHANI, C.ROSSI, A.ESTEVE

NEO

Revue Scientifique : Combustion and Flame, Vol.180, pp.10-19, Juin 2017 , N° 16410

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Abstract

This paper presents a hierarchical multiscale approach based on a micro-kinetic model enabling to predict temperature, pressure and species generated during the thermite reaction of Al nanoparticles mixed with CuO nanoparticles. Overall, our phenomenological model integrates and combines series of complex atomistic mechanisms, e.g. diffusion and phase transformation, gas phase reactions and interphase exchange mechanisms, in particular molecular condensation, evaporation and decomposition. Thermodynamics considerations as well as Density Functional Theory (DFT) calculations are used to implement rate equations expressing the complex reactions at solid/liquid/gas interphases. We demonstrate that the model can predict the pressure–time dependence, the different phases and compositions with good accuracy at significantly low computational cost. The influence of Al and CuO particle size, compaction or density, alumina shell thickness and stoichiometry on the pressure and temperature versus time is theoretically predicted with fairly good agreement with available experimental data. A maximum pressure of 47 MPa and adiabatic temperature of 3500 K are obtained at high compaction, i.e. 50% of the TMD (Theoretical Maximum Density) for stoichiometric mixture, where AlO is shown to be the prevailing gaseous species. At low compaction, we highlight the role of ambient oxygen condition for which the model gives a maximal pressure of 4.2 MPa for Al rich mixtures (stoichiometric ratio of 1.2).

139192
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