Papers by Author: Daniel Fruchart

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Authors: Elena Kurenkova, Anna Vyvodtseva, Marina G. Shelyapina, Vladimir I. Chizhik, Alexandr V. Ievlev, N.E. Skryabina, Anahit G. Aleksanyan, Daniel Fruchart
Abstract: According to 1H NMR study in fcc hydrides of disordered Ti-V alloys hydrogen atoms are distributed over both octahedral and tetrahedral sites. The occupancy of octahedral sites increases with the vanadium concentration. In hydrides of ternary Ti-V-Cr alloys hydrogen atoms occupy tetrahedral sites only.
Authors: Mohamed Balli, Osmann Sari, L. Zamni, A. Robert, J. Forchelet, Daniel Fruchart
Abstract: In this paper we investigate the performances of two bulk magnetocaloric refrigerants based on La(Fe,Co)13-xSix and prepared by powder metallurgy. Both materials were developed especially for a magnetic cooling machine. We have determined the magnetocaloric effect in term of temperature change under magnetic field using a test-bench with practical running conditions. ΔT was measured under 2 T and close to room temperature range. The obtained results will be compared with those of some reference materials reported in the literature. In addition, a composite material based on La(Fe,Co)13-xSix is proposed for magnetic systems using Ericsson and AMR cycles for refrigeration close to room temperature.
Authors: D. Boudemagh, Daniel Fruchart, R. Haettel, El Kebir Hlil, A. Lacoste, L. Ortega, N.E. Skryabina, Janusz Toboła, Pierre Wolfers
Abstract: Laves phases of C15 type of the system Mg2Si1-xSnx with x = 0, 0.4, 0.6 and 1 were synthesized in polycrystalline state in tantalum ampoule heated by high frequency coupling. The as-cast materials were analysed first at room temperature by X-ray diffraction (XRD). Systematically, XRD patterns were recorded up to 700 °C and Differential Scanning Calorimetry analysis was performed up to 1200°C to control the chemical and structural phase transformations. From these experiments, a C15 to C36 structure transformation was pointed out around 600°C in Mg2Si1-xSnx.solid solutions.
Authors: N.E. Skryabina, Daniel Fruchart, L. Cagnon, A.V. Shelyakov
Abstract: The creep deformation process initiated by hydrogen in both amorphous and nanocrystalline TiNi based alloys has been investigated. The mechanical behaviour has been interpreted in terms of microstructure phase transformations.
Authors: Daniel Rodrigo Leiva, André Castro De Souza Villela, Carlos de Oliveira Paiva-Santos, Daniel Fruchart, Salvatore Miraglia, Tomaz Toshimi Ishikawa, Walter José Botta Filho
Abstract: Magnesium complex hydrides as Mg2FeH6 are interesting phases for hydrogen storage in the solid state, mainly due to its high gravimetric and volumetric densities of H2. However, the synthesis of this hydride is not trivial because the intermetallic phase Mg2Fe does not exist and Mg and Fe are virtually immiscible under equilibrium conditions. In this study, we have systematically studied the influence of the most important processing parameters in reactive milling under hydrogen (RM) for Mg2FeH6 synthesis: milling time, ball-to-powder weight ratio (BPR), hydrogen pressure and type of mill. Low cost 2Mg-Fe mixtures were used as raw materials. An important control of the Mg2FeH6 direct synthesis by RM was attained. In optimized combinations of the processing parameters, very high proportions of the complex hydride could be obtained.
Authors: Viviane M. Azambuja, Dílson S. dos Santos, Daniel Fruchart
Abstract: . The Pd0.97Zr0.03, Pd0.97Ce0.03 and Pd0.97Ce0.015 Zr0.015 alloys were produced and studied in the present paper with respect to the hydrogen diffusivity and solubility. These alloys in the conditions as melted and cold worked, heat treated and also internally oxidized were submitted to hydrogen permeation tests. It was observed that the hydrogen diffusivity is strongly affected by the internal oxidation due to nano-oxides formation in the samples. On the other hand, the hydrogen solubility increases with introduction of defects as dislocations and vacancies introduced by cold working as well as the precipitates due to the internal oxidation. The nature, size and distribution of the precipitates and their influence on the hydrogen permeation parameters are discussed in this work.
Authors: Dílson S. dos Santos, S. Miraglia, Daniel Fruchart, Paul E. Valadao de Miranda
Authors: N.E. Skryabina, Lev Spivak, Daniel Fruchart
Authors: M. Bacmann, Daniel Fruchart, A. Koumina, P. Wolfers
Abstract: The magnetic structure of CrNiAs was determined from magnetisation and powder neutron diffraction experiments. In the 110-182 K temperature range, the compound is ferromagnetic, resulting mainly from the Cr moment of 1.25(5) μB. Below 110 K, neutron diffraction data reveals typical satellite reflections which propagation vector is 0.228 c*. A model of oscillating magnetic moments was refined from the integrated intensity of the few additional lines.
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