Control of substrate oxidation in MOD ceramic coating on low-activation ferritic steel with reduced-pressure atmosphere

摘要

An Er2O3 ceramic coating fabricated using the metal-organic decomposition (MOD) method on a Cr2O3-covered low-activation ferritic steel JLF-1 substrate was examined to improve hydrogen permeation barrier performance of the coating. The Cr2O3 layer was obtained before coating by heat treating the substrate at 700 degrees C under reduced pressures of <5 x 10(-3) Pa and 5 Pa. The Cr2O3 layer was significantly stable even with heat treatment at 700 degrees C in air. This layer prevented further production of Fe2O3, which has been considered to degrade coating performance. An MOD Er2O3 coating with a smooth surface was successfully obtained on a Cr2O3-covered JLF-1 substrate by dip coating followed by drying and baking. Preprocessing to obtain a Cr2O3 layer would provide flexibility in the coating process for blanket components and ducts. Moreover, the Cr2O3 layer suppressed hydrogen permeation through the JLF-1 substrate. While further optimization of the coating fabrication process is required, it would be possible to suppress hydrogen permeation significantly by multilayers of Cr2O3 and MOD oxide ceramic. (C) 2014 Elsevier B.V. All rights reserved.