Preparation and characterization of Er2O3-ZrO2 multi-layer coating for tritium permeation barrier by metal organic decomposition

Tritium permeation barrier coatings have been investigated for several decades to control tritium migration in fusion reactor fuel systems. In liquid lithium-lead blanket concepts, mitigation of not only tritium permeation through but also corrosion of structural materials is seriously required. In this study, for the development of a multifunctional coating, Er2O3-ZrO2 multi-layer coatings were prepared on reduced activation ferritic/martensitic steel substrates by metal organic decomposition. The deuterium permeability of the coated sample was three orders of magnitude lower than that of uncoated substrate in the first permeation experiment at 400 degrees C, and the high permeation reduction was kept in the temperature range of 400-650 degrees C. The coatings remained all over the sample surface after Li-Pb immersion experiments at 500-600 degrees C for 500 h, but were damaged at 600 degrees C. No reduction in coating thickness was confirmed after immersion at 550 degrees C by cross-sectional observation, suggesting that the multi-layer coatings may be applicable to the liquid lithium-lead blankets.