Dynamic mechanical analysis of hydrogen purification substrates and membranes

Porous 420 stainless steel hydrogen purification substrates were fabricated using an ExOne R2 printer and sintered at temperatures of 1075 °C and 1100 °C for times ranging from 15 minutes to 240 minutes. Coatings of 1 micron silica beads, silica sol-gel, and palladium were applied to the sintered structure. Mechanical properties/degradation of each substrate/coating combination were evaluated using a cyclic 3-point loading condition imposed by a TA Q800 dynamic mechanical analysis unit (DMA). A constant deformation procedure was used while the required drive force for deformation and the elasticity (tan delta) were recorded throughout the cycle. Findings with respect to coating additions include: drive force increases with the addition of each coating, tan delta decreases with ceramic additions and increases with palladium addition (eventually decreases when membrane fails), and tan delta values become comparable with the addition of palladium regardless of other parameters. Findings with respect to sintering time and temperature include: drive force increases with increased sintering time and temperature, tan delta increases with increased sintering time at 1075 °C, and tan delta decreases with increased sintering time at 1100 °C. Overall, the palladium layer would likely remain intact in service due to actual force oscillations not being as extreme in service, poisoning would likely be the life limiting factor.;Keywords: Sintering, dynamic mechanical properties, porous stainless steel, hydrogen purification, sol-gel.