Study on expansion characteristics of Al–Al₂O₃ composite seals for intermediate‐temperature solid oxide fuel cell

Al 2 O 3 ‐based composite seal with 10 wt% Al powder addition (A10) possesses excellent plastic and mechanical performance under wide temperature range of solid oxide fuel cell. The thickening phenomenon of A10 seal between 250°C–400°C and 600°C–750°C is caused by the thermal expansion of organic additives and the volume expansion when solid–liquid Al react with oxygen to form Al 2 O 3 . The thickness change rate reaches the maximum which is about 5% at 300°C and is about 4.46% at 650°C. The Gibbs free energy for reaction between Al and Al 2 O 3 in the temperature range of 523–1 023 K is all less than 0, which is proved by the fact that A10 exhibits excellent self‐expansion and thermodynamic properties in the solid oxide fuel cell operating temperature.