Investigation of crystallization kinetic of SrO-La_2O_3-A1_2O_3-B_2O_3-SiO_2 glass and its suitability for SOFC sealant

摘要

Strontium-lanthanum-aluminoborosilicate (SrO-La_2O_3-Al_2O_3-B_2O_3-SiO_2) (SLABS) glass was prepared for sealant material in planar Solid Oxide Fuel Cells (pSOFC). Differential Thermal Analysis of the glass showed the formation of two crystalline phases, first one 807 ℃ and the second phase at 1021 ℃. Crystallization kinetic of the first crystalline phase was investigated by differential thermal analysis (DTA) and using the JMA-kinetic model. The activation energy for crystallization was calculated to be 114.04 kJ/mol with frequency factor 5.9 × 10~3. Coefficient of Thermal Expansion (CTE) of the glass was measured to be 9.72 × 10 ~6/℃. Optical band gap of the glass was measured to be 3.07 eV. Conductivity measured by Impedance spectroscopy found to be 5.68 × 10 ~7 S cm at 600 ℃ and it increased with temperature to 2.68 × 10 ~6 S cm at 800 ℃. Activation energy for electrical conduction was measured to be 66.12 kj/mol. Wetting behavior of the glass on a ferritic steel substrate was investigated under hot stage microscopy. It showed initial deformation temperature (IDT) 754 ℃, softening temperature (ST) 840 ℃, hemispherical temperature (HT) 1108 ℃ and flow temperature (FT) 1279 ℃.