Mechanical properties evaluation method for non-stoichiometric materials under high temperature and oxidizing/reducing conditions

Abstract

For the commercialization of solid oxide fuel cell (SOFC), in addition to the electrochemical reliability, it is also important to ensure the mechanical reliability of SOFC. Thus, the establishment of a suitable mechanical testing method under various temperatures and oxygen partial pressure conditions is a prerequisite for the development of reliable SOFCs. In this study, the in-situ mechanical testing method was developed in order to investigate mechanical property (i.e.: Elastic modulus and Fracture strength, Creep and Fatigue property) of solid oxide fuel cells components under high oxidizing/reducing environments. And mechanical property of gadolinium doped ceria (Gd 0.1Ce 0.9O 2-δ; GDC) as oxygen non-stoichiometric compounds were evaluated in oxygen partial pressures under reducing conditions by developed In-situ mechanical testing machine. The experimental results of the investigation of elastic modulus and fracture strength on the SOFC components, the fracture stress of GDC were almost constant regardless of oxygen partial pressure, while elastic modulus decreased with decreasing oxygen partial pressure in reducing atmospheres. Mechanical properties of SOFC materials should be characterized by in-situ method because these results are different to quench method. © 2011 The Japan Society of Mechanical Engineers.