Compatibility of dip-coated Er2O3 coating by MOD method with liquid Li

An electrical insulating ceramic coating on the self-cooled lithium blanket is a promising technology for suppressing MHD pressure drop in the blanket system. Er2O3 is thought to be one of the potential candidate materials for ceramic coatings because of their high electrical resistivity and high compatibility with liquid lithium. In this study, Er2O3 coating was fabricated on the ferritic steels by dip-coating method with MOD (metal organic decomposition) liquid precursor followed by baking in different atmosphere. The coated specimens were immersed at 500 °C in the static liquid lithium to test the compatibility. It was shown that the compatibility of the coating was degraded when Fe2O3 or Fe3O4 was formed as the main composition of the substrate oxidation layer during the baking. On the other hand, thin Cr2O3 layer in the substrate oxidation layer did not influence the stability of Er2O3 coating. Atmosphere controlling for suppressing the substrate oxidation, especially Fe2O3 or Fe3O4, during the baking is shown to be essential for the compatibility of MOD Er2O3 coating on ferritic steels.