Jean-Claude Bernier

Synthesis of glass “precursor” BaO,TiO2,nH2O by gel processing

Abstract Sol-gel methods are currently applied for binary systems such as BaOTiO 2 using the alkoxide hydrolysis method. The control of hydrolysis kinetics with the use of weak concentration and low temperature leads to monolithic gels. The drying process stage leads to a gel-glass ceramic displaying small egg-shaped crystals of BaTiO 3 in a glass matrix at 725°C. The TGA, DTA and dilatometric curves of this glass are given with SEM studies.

Sintering of Nd2O3 and Ceramic Stability to Hydration

Study of the sintering of Nd2O3 made possible to determine the best conditions for its high densification. Unfortunately, the compacts show a very poor resistance to humidity. This is mainly due to the A hexagonal structure. Stabilization against hydration was attempted by coating the Nd2O3 grains, to avoid the existence of an interface oxide-OH-. Sintering of samples doped with TiO2 leads to the hexagonal oxide which appears as Nd2O3 particles surrounded by an intergranular phase. The later was identified as Nd2TiO5 by use of microprobe analysis. The resistance to hydration of A-Nd2O3 was then four times improved.