Fracture properties of nickel-based anodes for solid oxide fuel cells

Reliable assessment of structural integrity of fuel cells requires the knowledge of the mechanical properties of their individual components, in particular the fracture toughness. A technique is presented to measure the critical energy-release rate/fracture toughness of thin ceramic layers such as the anode material (NiO–YSZ) in a fuel cell. The approach involves a new specimen geometry which consists of a thin ceramic glued onto thick steel beams to form a double cantilever beam (DCB) specimen. The fracture toughness values, measured from truly sharp cracks, are obtained over a range of applied energy-release rates: from crack growth initiation to fast fracture. The fracture toughness is measured to be 1.97 ± 0.13 MPa m at crack growth initiation.