A hydrogen permeation barrier was manufactured by the in situ reaction of zirconium hydride with oxygen. A reduction in the hydrogen permeation of the oxide films was detected by measuring the mass difference of the zirconium hydride samples after the dehydrogenation experiment. The reaction of zirconium hydride with oxygen occurs only under the condition that the temperature is higher than 673 K in the oxygen partial pressure of 0.1 MPa. The oxide film is composed of two layers, a permeable oxide layer and a dense oxide layer, and the main phase of the oxide film is ZrO2 with baddeleyite structure. The XPS analysis shows that O-H bonds exist in the oxide film, which are helpful for resisting hydrogen diffusion through the oxide film.
Hydrogen desorption behaviors of zirconium hydride at temperature range of 100-900 ℃ in mixture gases of helium and oxygen was studied by gas phase analysis(GPA). Meanwhile,the morphologies of the oxide scale formed on the surface of zirconium hydride were analyzed by scanning electron microscopy(SEM). The hydrogen desorption is retarded effectively when zirconium hydride is exposed to an oxygen containing atmosphere. Hydrogen desorption in mixed gas of helium and oxygen starts at 525 ℃ and reaches maximum at 660 ℃ and ends eventually at 800 ℃. No hydrogen desorption is found at the temperature range from 800 ℃ to 900 ℃. An oxide scale with approximately 20 μm in thickness formed on the surface of zirconium hydride acts as an effective diffusion barrier.
