Crystallisation kinetics in AO-Al2O3-SiO2-B2O3 glasses (A = Ba, Ca, Mg)

The crystallisation kinetics of AO-Al2O3-SiO2-B2O3glasses (A = Ba, Ca, Mg) was investigated using DTA, XRD, and microstructural studies. Moreover, the influence of nucleating agentssuch as TiO2, ZrO2, Cr2O3, and Ni on MgO base glasses waselucidated. The glasses are of interest for the development ofsealants in Solid Oxide Fuel Cells (SOFC). The activation energy ofcrystal growth, E a, was evaluated for the different glassesusing the modified Kissinger equation. The preparation method of theglasses seems to determine whether surface or bulk nucleation is thedominant mechanism. The E a values vary between 330 and622 kJ/mol. The nucleating agents tend to enhance E a exceptZrO2. An increase of the Al2O3 concentration induces phaseseparation and decreases E a. The results are discussed onthe basis of the structural role and chemical properties of the Alions as well as with respect to the possible use of the glasses inSOFC.