Fabrication and characterization of enamel coating as a promising hydrogen and oxygen diffusion barrier

• Published in: Fusion engineering and design Vol. 204; p. 114506
• Main Authors: Shimizu, Yuka, Fujiwara, Hikaru, Shirota, Kento, Matsuura, Wataru, Ito, Tetsuma, Do-Duy, Khiem, Chikada, Takumi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2024
• Subjects: Coating; Enamel; Permeation; Silicon dioxide; Tritium; Tritium; Coating; Enamel; Silicon dioxide; Permeation
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2024.114506

Functional coatings to tritium permeation and corrosion by tritium breeders have developed in fusion reactor blanket systems. Ceramic coatings such as metal oxides show high hydrogen isotope permeation reduction performance; however, oxidization of steel substrates by oxygen diffusion through the coating at high temperatures causes degradation of the coating. In this study, we fabricated enamel coatings consisting primarily of silicon dioxide that had a low oxygen diffusion coefficient and analyzed microstructure and deuterium permeation properties as a promising functional coating. The smooth enamel coatings with the thickness of less than 20 μm were successfully fabricated on stainless steel substrates using a dip-coating technique and heat-treatment at more than 700 °C. The deuterium permeation reduction of this coating was 8000 times higher than the substrate at 600 °C although there is no reduction at high temperature measurements. These results suggest that the enamel coating is applicable to the hydrogen isotope permeation barrier.