Abstract
The effect of water vapor on the mechanical properties of a porous nickel/yttria-stabilized zirconia (Ni–YSZ) composite (volume ratio of Ni:YSZ = 40:60) was evaluated at 850°C, a typical operating temperature of a reversible solid oxide cell. Both the flexural strength and static fatigue limit of Ni–YSZ obtained from the static fatigue lifetime under a wet atmosphere (containing 4% H2O) were lower than those under a dry atmosphere. This can be explained by absorption of H2O molecules into YSZ particles, resulting in accelerated crack growth. The fatigue limit of Ni–YSZ was confirmed to be extremely low, corresponding to almost one-third of the flexural strength.
