Deuterium permeation behavior of tritium permeation barrier coating containing carbide nanoparticles

Highlights: • Y₂O₃ coatings with carbide nanoparticles were fabricated by metal organic decomposition. • Deuterium permeation through Y₂O₃ coatings containing carbide nanoparticles was examined. • The permeability varied by fabrication process with and without pretreatment. • The coatings showed approximately 1000 times lower permeability than uncoated substrate. • Agglomerated nanoparticles in the liquid precursor led to peeling after heat treatment. - Abstract: Y₂O₃ coatings containing Cr₃C₂ nanoparticles have been prepared on reduced activation ferritic/martensitic steel F82H substrates by metal organic decomposition with dip-coating technique, and their deuterium permeation behaviors have been investigated. The surface condition of the samples varied with pre-treatment process: fabrication of Y₂O₃ coatings without the Cr₃C₂ nanoparticles or surface oxidation of F82H. In the coating without pre-treatment, peeling of agglomerated nanoparticles and oxidation of the substrate at the peeled regions were observed. Pores were also observed in the coatings with pre-treatment; however, iron oxide was not formed. The deuterium permeation flux of the coating fabricated without pre-treatment was lower than that of uncoated F82H substrate by a factor of 100 even after crystallization at 700 °C. In the case of the sample with pre-treatment, the permeation flux was by a factor of 100 lower than that of uncoated substrate before crystallization, and the factor increased to approximately 1000 after crystallization. Dispersion of the nanoparticles and securement of surface coverage of the coating are key factors to establish high-performance tritium permeation barrier.