Keywords: Hydrogen embrittlement

Hydrogen in metallic materials causes degradation known as hydrogen embrittlement, which renders the materials brittle. Therefore, to promote the use of hydrogen energy in applications such as fuel cells and nuclear fusion reactors, strategies to prevent hydrogen permeation into structural materials are essential. In this study, we elucidated the mechanism by which coating multiple layers of different ceramic films on metal surfaces, which serve as hydrogen permeation barriers, can more effectively suppress hydrogen permeation than single-layer ceramic films. This research can contribute to extending the service life of metallic materials in a hydrogen environment.