Study of the Crystallization in a Glass-Ceramic Seal
Résumé
Sealing is a major issue in Solid Oxide Cells (SOC) stacks used for
hydrogen production. The specifications that seals must meet are
particularly demanding. Glass-ceramics such as materials from the
MgO-Al2O3-BaO-SiO2-B2O3 system are used. A preliminary
treatment allows the initially amorphous material to set up while
partially crystallizing. This paper presents the crystallization study
of such a material.
The main Ba5Si8O21 and BaMg2Si2O7 crystalline phases are
identified and the evolution of crystals morphology with the
temperature is followed. The BaxSiyOx+2y surface fraction is
determined by image analysis as a function of time and temperature.
These data allow accessing the equilibrium crystal fraction. It is then
possible to optimize the crystallization treatment and to anticipate
the microstructural evolution of the glass-ceramic seal operating in
the stack.
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