Effect of nano-layered ceramic coatings on the electrical conductivity of oxide scale grown on ferritic steels.

The electrical conductivity of a coated and uncoated model Fe-30Cr ferritic steel was studied between 973 and 1,073 K. The ASR values decreased with temperature increase. The application of a nano-structured ceramic coating made of yttria on the surface of the steel induced a decrease of the ASR values, especially at 1,073 K, which is the operating temperature for Intermediate Temperature Solid-Oxide Fuel Cells. The ASR value of the yttria-coated alloy is 9.3 mΩ cm² compared to 37.8 mΩ cm² determined on the uncoated steel after 100 h at 1,073 K in air. The estimated value of the ASR parameter after 10,000 h is encouraging, as it is limited to 17 mΩ cm². The oxidised surfaces were characterised by scanning electron microscopy and X-ray diffraction. The results were compared with the literature. [ABSTRACT FROM AUTHOR]