Al-B-C ternary compounds : synthesis, structure, composition and thermal stability

International audienc

Al-B-C ternary compounds : synthesis, structure, composition and thermal stability

International audienc

Analyse thermique dans l'étude des boranes pour le stockage solide de l'hydrogène

National audienc

Borohydride-induced destabilization of hydrazine borane

International audienc

Ammonia borane decomposition in the presence of cobalt halides

International audienc

Synthesis of manganese oxide supported on mesoporous titanium oxide: Influence of the block copolymer

SSCI-VIDE+CARE:CDFA+FSC:MBE:CDSInternational audienceManganese oxides supported on mesoporous titanium oxides were synthesized via a sol-gel route using block copolymer self-assembly. The oxides were characterized by X-ray diffraction, infrared spectroscopy, thermal analyses, nitrogen adsorption/desorption, electron microscopy and electronic paramagnetic resonance. A mesoporous anatase containing amorphous manganese oxide particles could be obtained with a 0.2 Mn:Ti molar ratio. At higher manganese loading (0.5 Mn:Ti molar ratio), segregation of crystalline manganese oxide occurred. The influence of block copolymer and manganese salt on the oxide structure was discussed. The evolution of the textural and structural characteristics of the materials upon hydrothermal treatment was also investigated. (C) 2014 Elsevier Inc. All rights reserved

High-temperature-reactivity of Al–Ti alloys in contact with SiC

International audienceSeveral industrial processes involving SiC coupling to Al-Ti alloys (e.g. metallization of SiC components, brazing of SiC parts) require an in-depth knowledge of Al-Ti/SiC interactions occurring at high temperatures. To this end, the surface reactivity between SiC and Al-Ti alloys (Al3Ti and (Al+Al3Ti) systems) was analyzed by specific experiments (wetting, DSC, microstructural examinations) as well as by a thermodynamic approach (CALPHAD method). An Al-C-Si-Ti thermodynamic database was successfully established to calculate several sections and projections in order to compare the computed, expected solid phases formed at the interface with those characterized in wetting experiments. In this way, the change in liquid and solid phases was interpreted and discussed, defining the Ti3(Al,Si)C2 mixed MAX-phase as the main interfacial product created by thechemical reaction, as a function of temperature and alloy composition. This work constitutes a guide for the choice of operating parameters in processes such as brazing or SiC metallization in microelectronic applications, in which the control of interfacial products is one of the most delicate production steps. The approach proposed to monitor the pathway of liquid composition with time and temperature during liquid/solid interaction, successfully applied to interpret the microstructure obtained in wetting experiments, is a promising method for interpreting more complex cases such as homogeneous or even heterogeneous brazing processes