Mechanical properties of solid oxide fuel cell glass-ceramic seal at high temperatures

► Glass-ceramic SOFC seal material is characterized using high temperature nanoindentation. ► Aging of the glass-ceramic seal material is varied. ► Test temperatures include 25, 550, 650, and 750 °C. ► Results show decrease in reduced modulus and hardness with increasing temperature. ► Results show decrease in creep after longer aging. Mechanical properties of solid oxide fuel cell glass-ceramic seal material, G18, are studied at high temperatures. Samples of G18 are aged for either 4 h or 100 h, resulting in samples with different crystallinity. Reduced modulus, hardness, and time-dependent behavior are measured by nanoindentation. The nanoindentation is performed at room temperature, 550, 650, and 750 °C, using loading rates of 5 mN s −1 and 25 mN s −1. Results show a decrease in reduced modulus with increasing temperature, with significant decrease above the glass transition temperature. Hardness generally decreases with increasing temperature, with a slight increase before Tg for the 4 h-aged sample. Dwell tests show that creep increases with increasing temperature, but decrease with further aging.