Deuterium permeation and retention behaviors in erbium oxide-iron multilayer coatings

• Published in: Fusion engineering and design Vol. 124; pp. 1086 - 1090
• Main Authors: Horikoshi, Seira, Mochizuki, Jumpei, Oya, Yasuhisa, Chikada, Takumi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2017; Elsevier Science Ltd
• Subjects: Arc deposition; Ceramic coating; Ceramic coatings; Ceramics; Deuterium; Diffusion; Diffusion barriers; Diffusion coating; Diffusion layers; Diffusion model; Electron tubes; Erbium; Erbium oxide; Ferritic stainless steels; Foils; Fuel systems; Fusion; Grain boundaries; Grain boundary diffusion; Grain structure; Hydrogen isotopes; Hydrogen storage; Magnetron sputtering; Martensitic stainless steels; Multilayers; Nuclear reaction analysis; Nuclear reactors; Structural analysis; Substrates; Thickness; Tritium; Tritium permeation barrier; Nuclear reaction analysis; Ceramic coating; Erbium oxide; Tritium permeation barrier; Diffusion model
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2017.03.123

•Deuterium permeation behavior in ceramics-metal multilayer coatings were investigated.•The grain boundary diffusion model was established with deuterium depth profiles.•Deuterium permeabilities of two-layer coating were comparable with that of Er2O3 coating.•Two Er2O3 layers in three-layer coatings worked as permeation barriers independently.•Increase of tritium retention in multilayer coatings is negligibly small. Hydrogen isotope migration behaviors in ceramics-metal multilayer coatings have been elucidated for a further improvement of fueling system and radiological safety. Erbium oxide (Er2O3) coatings were fabricated by filtered vacuum arc deposition (VAD) on reduced activation ferritic/martensitic steel substrates. An iron (Fe) layer was fabricated by radio-frequency magnetron sputtering or covered with an Fe foil on the Er2O3 coating. An Er2O3-Fe-Er2O3 three-layer coating was also fabricated by the VAD on the Er2O3-Fe coating. The grain boundary diffusion model was constructed based on the results of grain structure analysis and deuterium depth profile for the Er2O3 single-layer coating from our previous works. The Er2O3-Fe two-layer coatings with different Fe layer thickness showed no significant difference in deuterium permeability. The Er2O3-Fe-Er2O3 three-layer coating showed a PRF of up to 104 due to a contribution of two diffusion barriers of the inner and outer Er2O3 layers. In addition, the three-layer coating had three times higher deuterium concentration than the Er2O3-Fe coating, although the concentration will be negligibly small from the perspective of tritium inventory in the fuel system.