ドメイン配向を制御したLaCoO₃の作製

抄録

In recent years, many studies have been conducted on fuel cells, and among them, solid oxide fuel cells (SOFC) are highly resistant to corrosion and high temperatures, and are expected to be highly practical because they can be used as large stationary fuel cells. This research focuses on LaCoO3 (LCO), which is expected to be used as an air electrode and electrolyte for SOFC, and as an oxygen separation membrane for oxygen combustion technology. Lanthanum perovskite oxides containing LCO have been reported to exhibit unique nonlinear behavior. This is related to the ferroelasticity domain existing in the LCO. It has been confirmed that this ferroelasticity domain has the orientation, when it is observed in scanning electron microscope (SEM). Therefore, by controlling the orientation of the ferroelasticity domain, the addition of new mechanical properties and the improvement of ion conductivity performance can be expected. Experimental method. LCO has the property that the domain orientation disappears above 1273 [K] and reorients when it is lowered to room temperature. Therefore, the orientation is controlled by applying uniaxial compressive stress or creep stress at a high temperature (573 [K], 773 [K]). Results. By applying uniaxial compressive stress, reduction of critical stress and increase of maximum strain were confirmed. And, the lowering of the critical stress was confirmed by applying the creep stress.