Investigation of crystallization kinetic of SrO–La2O3–Al2O3–B2O3–SiO2 glass and its suitability for SOFC sealant

Abstract

Strontium–lanthanum–aluminoborosilicate (SrO–La2O3–Al2O3–B2O3–SiO2) (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 °C and the second phase at 1021 °C. 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 × 103. Coefficient of Thermal Expansion (CTE) of the glass was measured to be 9.72 × 10−6/°C. 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−1 at 600 °C and it increased with temperature to 2.68 × 10−6 S cm−1 at 800 °C. 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 °C, softening temperature (ST) 840 °C, hemispherical temperature (HT) 1108 °C and flow temperature (FT) 1279 °C.