Etude des problemes poses par l'elaboration de fils supraconducteurs gaines argent a haute temperature critique

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 82674 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Characterization of the precipitation of Oxide Dispersion Strengthened (ODS) ferritic steels reinforced by Y2_2 Ti2_2O7_7 pyrochlore phase

International audienc

Procédé de fabrication d'une piece en un materiau composite Al/Al3B48C2

The invention relates to a method for manufacturing a part made of a composite material Al / Al3B48C2 comprising an aluminum matrix in which particles of a mixed carbide of chemical formula Al3B48C2 are dispersed. The method comprises the following steps: a) the introduction of a powder of chemical formula AlB 2 into the cavity of a graphite crucible; b) closing the cavity by a graphite element; c) heating the crucible at a temperature of at least 960 ° C and less than or equal to 1400 ° C to obtain the formation of mixed carbide precipitates of chemical formula Al3B48C2 in liquid aluminum; d) cooling the crucible to solidify the liquid aluminum; e) elimination of the crucible; whereby the piece of Al / Al3B48C2 composite material is obtaine

Investigation of nanoporous carbon powders produced by high energy ball milling and formation of carbon nanotubes during subsequent annealing

Nanoporous structure was found in graphite samples after ball milling at ambient temperature. The internal micropore surface area, as determined using the T-plot method, was found to vary during milling, in association with phase transformations of the graphite. Structural changes from hexagonal to turbostratic, and to amorphous phases were observed and investigated using X-ray diffraction analysis and transmission electron microscopy. Carbon nanotubes were obtained by the annealing of the milled samples at 1400°C for 6 hours in nitrogen gas

Nanoporous Carbon Produced by Ball Milling

Ball milling of graphite powder at room temperature resulted in the formation of disordered and nanoporous carbon powder. Agglomeration of the nanosized and disordered layers under ball impacts formed the micropores. Transformations from hexagonal to turbostratic, and to amorphous phase were observed

X-Ray diffraction study of oxygen deficient Y2Ti2O7-δ pyrochlore powders synthesized by high-energy ball milling (HEBM)

International audienceY2Ti2O7 pyrochlore are widely used for various applications, from oxygen transport to materials strengthening. Ultra-pure oxygen deficient Y2Ti2O7-δ pyrochlore powders synthesized by high-energy ball milling (HEBM) are studied by X-ray diffraction (XRD). Rietveld analysis of diffraction patterns reveals that a large oxygen sub-stoichiometry can be accommodated in this material with only minor structural changes. This accommodation results from the ability of Ti ions to change their valence state, which is confirmed by complementary EELS analysis. It may also explain why Y2Ti2O7 is both radiation and mechanical milling resistant. This work highlights the fact that selection of cations allows rigid ionic structures like pyrochlore to accommodate a large amount of point defects

Etude des problemes poses par l'elaboration de fils supraconducteurs gaines argent a haute temperature critique

SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : RM 1594 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc