Influence of a coating on oxidation resistance and resistivity of a chromia former alloy for high temperature vapor electrolysis application

Alloy 230 was studied as possible interconnect material for high temperature vapor electrolysis (HTVE) application. For such a use, the main important requirements are good corrosion resistance and a low area specific electrical resistance (ASR). The samples were oxidized at 800 C for 250 h under cathodic (Ar-1 %H₂-9 %H₂O) and anodic (dry air) HTVE atmospheres. In situ ASR evolution of alloy 230 in both conditions was determined using a specific device. The influence of a LaCrO₃ coating is also discussed in this study. It is shown that alloy 230 offers good corrosion resistance, improved by the presence of the coating. A calculation of the theoretical ASR is in good agreement with the experimental value obtained in anodic environment. For the cathodic condition, the ASR value is two orders of magnitude higher than the expected one, and this could be explained by the presence of hydrogen in the oxide layer. The LaCrO₃ coating effect on ASR values remains unclear, but it appears to have at least an influence on its evolution over the test duration. (authors)