Effect of Electric Current on Growth of Oxide Scale on Fe–25Cr Alloy for SOFC Interconnect at 1073 K

Fe–25Cr ferritic alloy was oxidized at 1073 K under the electric current flow, 0.50 A cm −2 , with exposing anode and cathode atmospheres simulating the operating condition of SOFC. The morphology of scale is almost same between with current and without current. The oxide scales are composed of and small amount of spinel which dispersed on the surface of the scale. The thickness of scale at anode side with current is thicker than that without current and that at cathode side with current is thinner than that without current. The scale thickness with electric current could be represented by the formula based on Wagner's theory for high temperature oxidation. And the formula derives the transference number of Cr ion, t Cr in scale was obtained as 1.8 × 10 −6 .