GROSSEAU , Philippe

Az alumínium-oxid alapú kerámiaanyagok tekinthetok az elsö modern kerámiáknak, melyek mind technológíai mind tudományos szempontból kiemelkedö fontosságúak. Feldolgozási technológiájuk és tulajdonságaik javulása igen szoros kapcsolatban van a szinterelésük mechanizmusára vonatkozó ismeretek bóvülésével1. A szinterclés a szilárd anyagok...

Thanks to its high thermal conductivity, aluminum nitride may be a serious candidate as fuel coating for the Gas Fast Reactor. However, its behavior under irradiation is not entirely well understood. In order to catch a glimpse of this behavior, specimens were irradiated with swift heavy ions of different energies then characterised by both...

Thanks to its high thermal conductivity, aluminum nitride may be a serious candidate as fuel coating for the Gas Fast Reactor. However, its behavior under irradiation is not entirely well understood. In order to catch a glimpse of this behavior, specimens were irradiated with swift heavy ions of different energies then characterised by both...

Thanks to its high thermal conductivity, aluminum nitride may be a serious candidate as fuel coating for the Gas Fast Reactor. However, its behavior under irradiation is not entirely well understood. In order to catch a glimpse of this behavior, specimens were irradiated with swift heavy ions of different energies then characterised by both...

The dependence of the firing conditions on the crystal structure formation of ZnGa2 O4 has been investigated. The effects of temperature and atmosphere were examined and gave evidence of the instability of the zinc gallate under a reducing atmosphere at temperatures above 600°C. A new preparation route has allowed to synthesize ZnGa2 O4 at...

The formation of SrAl2O4 by solid state reaction between SrCO3 and Al2O3 has been studied. The firing conditions, namely the time, the atmosphere and the temperature, have been optimized so as to obtain pure well crystallized SrAl2O4, allowing the further study of the influence of the atmosphere on the optoelectronic properties of the phosphor....

Alpha alumina powders have been produced by thermal treatment under controlled atmosphere of highly pure gamma alumina. The influence of the atmosphere and the addition of dopants (Mg2+, Cr3+, Th4+) were studied by thermoluminescence (TL). TL is a technique which gives information about point defects. It allowed to reveal the presence of oxygen...

Doped alpha-alumina powders have been synthesised by thermal treatment of gamma-alumina under a controlled atmosphere. Two TL peaks, located at 200°C and 365°C, have been detected in almost all samples. Their intensity is strongly dependent on the atmosphere and on the nature of introduced dopants. The influence oh these parameters on point...

Two parameters were studied upon the thermoluminescence (TL) properties and the sintering behaviour of α-alumina: the atmosphere during the heat treatment used to transform γ-Al2O3 into α-Al2O3 and the doping by Zr and Th. It appears that a reducing atmosphere tends to delay the sintering compared with the oxidising atmosphere until 1600°C....

The thermoluminescence method (TL), or the thermostimulated luminescence is one of the techniques which correlate thermal and optical methods and usually used to characterize the defects occuring in insulating or semiconductors materials. After a brief description of the TL phenomenon based on the example of alpha alumina, we present some...

The dependence of the firing conditions on the crystal structure formation of ZnGa2O4 has been investigated. The effects of temperature and atmosphere were examined and gave evidence of the instability of the zinc gallate under a reducing atmosphere at temperatures above 600 degrees C. A new preparation route has allowed to synthesize ZnGa2O4...

Two parameters were studied upon the thermoluminescence (TL) properties and the sintering behaviour of a-alumina: the atmosphere during the heat treatment used to transform gamma -Al2O3 into alpha -Al2O3 and the doping by Zr and Th. It appears that a reducing atmosphere tends to delay the sintering compared with the oxidising atmosphere until...

For Generation IV reactors, and more particularly the Gas Fast Reactor, aluminum nitride is an interesting candidate for the application as fuel coating; actually, its great thermal conductivity should allow efficient thermal transfer between the fuel pellets and the coolant. Unfortunately, few data are available on its behavior under...

Pure Al2O3 powders have been prepared by thermal decomposition of ammonium alum (NH4Al(SO4)2. 12H2O). The calcinations were performed at different temperatures, and under flowing oxygen or nitrogen or hydrogenated argon. The thermoluminescence of these powders after X ray irradiation at room temperature is studied from room temperature to 780...

LaPO4:Ce, Tb (LaCeT) is a green phosphor used in fluorescent lamps and plasma display panels. In order to improve the fabrication process of this phosphor, different fluxes have been used. Their influence on the particles size and shape is described thanks to SEM analyses. Fluxes were found to control the morphology of particles : LaCeT...

The thermoluminescence (TL) and fluorescence spectra of magnesium aluminium oxynitride "MgAlON" and magnesium aluminate MgAl2O4 spinel powders have been analysed. Two broad peaks at about 100 and 300 °C appear in the TL spectra of MgAl2O4 and seem to be related to electron and hole release from [AlMg√] and [MgAl′] traps, respectively. The...

The thermoluminescence (TL) after excitation by UV or X-rays radiation of alumina-zirconia powders is investigated. The composites present five of the characteristic peaks of zirconia at −170, −145, −90, 0 and 95 °C. After a thermal treatment of mixed oxides, a new peak is observed at −35 °C in TL. This peak reveals the presence of stabilized...

Comme pour tout système nucléaire, le concept du combustible pour les réacteurs de IVème génération consiste en des pastilles de combustible conditionnées dans une matrice qui doit contenir les produits de fission. De par leur excellente réfractarité, les carbures sont pressentis pour constituer cette barrière de confinement. Parmi ceux...

The Ti3SiC2 refractory compound that combines properties of both metals and ceramics is a fuel cladding candidate under investigation for Gas-cooled Fast Reactor. Its behavior under swift heavy ion irradiation (Xe ions, 92 MeV, 1019 m−2) was investigated. Significant and unexpected surface changes have been highlighted: hills have been observed...

Thanks to their refractoriness, carbides are sensed as fuel coating for the IVth generation of reactors. Among those studied, the Ti3SiC2 ternary compound can be distinguished for its noteworthy mechanical properties: the nanolamellar structure imparts to this material some softness as well as better toughness than other classical carbides such...

The thermoluminescence (TL) after excitation by UV or X-rays radiation of doped a-alumina powders is investigated. In the case of zirconia, the alumina-zirconia composites present five of the characteristic peaks of zirconia at -170, -145, -90, 0 and 95°C. After a thermal treatment of mixed oxides, a new peak is observed at -35°C in TL. This...

The concept of the fuel for the IVth generation reactors should consist of fuel pellets surrounded with a matrix that must contain fission products. Thanks to their interesting thermo-mechanical properties, carbides are sensed to become this matrix. Among the studied carbides, Ti3SiC2 can be distinguished; actually, its nano-laminated structure...

Ce travail porte sur l'amélioration du procédé de fabrication des luminophores et en particulier un phosphate de lanthane : LaPO4:Ce,Tb (LaCeT). L'influence de fondants carbonatés (Li2CO3, Na2CO3, K2CO3, ...) sur la taille et la forme des grains du luminophore y est décrite. Pour ce faire des analyses par microscopie électronique à balayage ont...

Les carbures, de par leurs propriétés remarquables, sont pressentis comme matériau de structure autour du combustible du réacteur de génération IV. Parmi ceux étudiés, Ti3SiC2 se distingue car il associe les propriétés des céramiques à celles des métaux. Cependant, son comportement sous irradiation n'est pas connu. Des caractérisations ont été...

Thanks to their refractoriness, carbides are sensed as fuel coating for the IVth generation of reactors. Among those studied, the Ti3SiC2 ternary compound can be distinguished for its noteworthy mechanical properties: the nanolamellar structure imparts to this material some softness as well as better toughness than other classical carbides such...