Effect of thickness and porosity on the mechanical properties of planar components for solid oxide fuel cells at ambient and elevated temperatures

The effects of specimen thickness and porosity on the elastic moduli, equibiaxial strength, and fracture toughness of planar solid oxide fuel cell components are reported. The tested materials include 8mol% yttria-stabilized zirconia (YSZ) electrolytes, and unreduced NiO/YSZ anodes. The thickness of these components varied between 0.5 and 1.5 mm, while the porosity varied between 6 and 23 % vol. Test specimens were processed by tape casting techniques and inspected by Infrared Imaging and Resonant Ultrasound Spectroscopy (RUS). These non-destructive evaluation techniques revealed the existence of defects, such as delamination. The equibiaxial flexural strength was determined by the ring-on-ring test method (ASTM C1499) while the fracture toughness was determined according to the double-torsion test method. Tests were carried out at ambient and elevated temperatures in air.