Nanocrystalline microstructure in Sm3+ and Gd3+ doped K2O–MgO–Al2O3–SiO2–F glass-ceramic sealant (SOFC)

摘要: In order to demonstrate the effects of Sm3+ and Gd3+ ions on crystalline microstructures magnesium-boro-alumino-silicate (MBAS) system, K2O–MgO–B2O3–Al2O3–SiO2–F glass doped with 0–5 mol% Sm2O3 Gd2O3 were synthesized by melt-quenching (1550 °C). The addition content was found increase density (2.74–2.91 g cm−3) base glass. By controlled heat-treatment at 950 °C, MBAS glasses converted into opaque glass-ceramics phases (XRD), containing fluorophlogopite mica [KMg3(AlSi3O10)F2], norbergite [Mg2SiO4·MgF2] enstatite [MgSiO3]. FESEM study revealed development rock-like plate-like crystallite particles (average size 2–4 μm) randomly dispersed in heat-treated microstructure, which is restructured nanocrystalline (size = ∼50–400 nm) morphology. substantial change microstructure influenced corresponding thermal expansion properties. coefficient for estimated be 10.47(±0.10) × 10−6 K−1 (50–800 °C), increased 11.11–11.29 when Gd3+. Such large makes Sm2O3- Gd2O3-doped suitable high temperature sealing applications (like SOFC).