Deuterium Permeation in an Er2O3 Thin Film Fabricated on a Type-316L Stainless-Steel Substrate

A metal-oxide film can be used as a hydrogen-isotope permeation barrier in a fuel circulation system for nuclear fusion. We fabricated an Er2O3 thin film on a type-316L stainless-steel substrate by using a metal-organic chemical vapor deposition technique for use as a hydrogen-isotope permeation barrier. Electron-microscopy-based imaging and energy-dispersive X-ray spectroscopy measurements, together with X-ray diffraction experiments, indicate a sound film quality. We also measured deuterium permeation in the film at high temperatures ranging from 600 ?C to 800 ?C. The permeation reduction was most apparent at 650 ?C. Above 800 ?C, we confirmed that the film was damaged and did not work as a permeation barrier.