Measurement of hydrogen isotope concentration in erbium oxide coatings

•We measure hydrogen isotope concentration in erbium oxide coatings.•Hydrogen isotope adsorption on the coating is observed.•Deuterium forms a chemical bond with carbon in sample fabricated by metal organic decomposition.•High grain-boundary area density increases deuterium concentration.•Deuterium concentrates in particular place which seems grain-boundary.

Hydrogen isotope concentrations in erbium oxide coatings fabricated by filtered arc deposition and metal–organic decomposition have been investigated using nuclear reaction analysis and secondary ion mass spectroscopy. It was found that the deuterium concentration in the coatings fabricated by filtered arc deposition was 300–500 atomic parts per million, whereas the deuterium concentration in the coating fabricated by metal–organic decomposition was approximately 2.0 × 104 atomic parts per million due to hydrogen trapping by carbon impurities. Deuterium concentrations in the coatings fabricated by filtered arc deposition increased with increasing depth in accordance with the increase of grain boundary area density. An in-plane deuterium distribution of the coating by secondary ion mass spectroscopy proved segregation with a net-like structure, indicating that the deuterium diffused through the grain boundaries.