Hydrogen charging effects on the alternation of oxide film formed on Ni, Cr and Alloy 690 in high-temperature water

The effects of hydrogen charging on the oxide film of Ni, Cr and Alloy 690 in high-temperature water were studied. Hydrogen was charged to the specimen during experiments. The inner layer of Cr exhibited amorph-ization after the hydrogen charging. The oxide film became thinner for Ni after hydrogen charging, and lots of cavities were observed along the boundary of inner oxide and matrix. The oxide film of Alloy 690 exhibited a mixed feature of Ni and Cr. The hydrogen diffusing to the solution not only affected the thermal stability of the oxide but also hindered the precipitation of outer oxide.

Automated summary

This study investigated the effects of hydrogen charging on the oxide film of Ni, Cr, and Alloy 690 in high-temperature water. The results showed that hydrogen charging caused amorphization in the inner layer of Cr, thinning of the oxide film in Ni, and the presence of cavities along the boundary of inner oxide and matrix. The oxide film of Alloy 690 exhibited a mixed feature of Ni and Cr. The diffusion of hydrogen into the solution not only affected the thermal stability of the oxide film but also hindered the precipitation of outer oxide.