Synthesis of YAG nanopowder by the co-precipitation method: Influence of pH and study of the reaction mechanisms

International audience; YAG nanopowders with an average grain size of 30 nm have been successfully synthesized by the co-precipitation method using nitrates with precipitant of ammonium hydrogen carbonate. The influence of precipitation conditions such as pH, aging time and calcination temperature on the formation of secondary phases has been studied. The accurate control of pH value at every stage of precipitation process is crucial to avoid the presence of YAM (Yttrium Aluminium Monoclinic, Y4Al2O9) and yttrium oxide (Y2O3) after calcination. The reaction mechanisms have been investigated using different techniques such as infrared spectroscopy, x-ray diffraction and thermal analyses. The…

Control of barium ferrite decomposition during spark plasma sintering: Towards nanostructured samples with anisotropic magnetic properties

Abstract The sintering of barium ferrite (BaM) nano-sized powders by spark plasma sintering was studied. At the surface of the samples, an iron-rich layer (magnetite) was formed due to the decomposition of BaM and segregation in the secondary phases. To prevent the formation of secondary phases different protection layers between the graphite mould and the sample were used. Their effect on the sample microstructure was studied by X-ray diffraction and scanning electron microscopy. The most suitable protection layer was a highly dense sintered disc of aluminium oxide. Using this dense protection layer, sintered discs of BaM with 82% of theoretical density and grains of 90 ± 50 nm were obtain…

Sintering of lead phospho-vanadate by spark plasma sintering

International audience

Nano-SiC/CNT composites sintered by SPS: CNT amount effect on mechanical, thermal and electrical properties

International audience

Propriétés mécaniques, thermiques et électriques de composites à matrice SiC nanostructurée renforcée de nanotubes de carbone

International audience

Advanced Usage of SPS Technology for Producing Innovative Materials

Propriétés mécaniques, thermiques et électrioques de composites à matrice SiC nanostructurée renforcée par des nanotubes de carbone

International audience

The materials saga: sintering

In ICV no 1010, we inaugurated our materials saga with the classification and shaping of ceramics. This second and short chapter deals with sintering and its different forms: non reactive or reactive sintering, natural or pressure sintering as well as two essential parameters: density and porosity.

In situ study of the sintering of a lead phosphovanadate in an Environmental Scanning Electron Microscope

cited By 3; International audience; The in situ sintering of a powder of Pb3(VO4) 1.6(PO4)0.4 composition was performed in an Environmental Scanning Electron Microscope. The electric current induced by the electron beam was found to reduce the effective temperature of sintering as well as to accelerate the kinetics of shrinkage of a cluster composed of sub-micrometric grains of material. The presence of the residual current flow in the cluster during observation for in situ experiments helps to reduce the apparent sintering temperatures from 50 to 150 °C compared to conventional heating conditions without current. © 2011 Elsevier B.V. All rights reserved.

Utilisation de la technique de frittage flash pour la synthèse et la densification d'iodoapatites

Composites nano-SiC/Nanotubes de carbone frittés par SPS: Elaboration et influence de la teneur en NTC sur les propriétés mécaniques

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Temperature control during Spark Plasma Sintering and application to up-scaling and complex shaping

International audience; The determination and the homogeneity of the sample temperature during consolidation of powders by Spark Plasma Sintering (SPS) are addressed. Densifications were carried out in three different facilities differing by their constructors and their size. A structural transformation activated in a TiAl alloy was used as a marker of the sample temperature and finite element modeling were performed to evaluate the temperature at each point of the set-up. A good agreement between experimental and simulated data is exhibited. Alloys with identical microstructures were sintered and the homogeneity of the microstructure was better in the largest machines or when the sample wa…