Formation of hydrogen resistant oxides of titanium alloy in water corrosion environment

The structure changes and hydrogen permeation behavior of Titanium alloy TA17 in simulated water environment of small modular reactor (SMR) at 320 °C for 8000h was investigated. We found a corrosion layer consist of TiO 2 and FeTiO 3 with a good hydrogen permeation resistance. The structure and hydrogen permeation resistance change with the increase of corrosion period. At the first corrosion period of 3000h, FeTiO 3 grows rapidly with an exponential parameter of 0.663 fitted by parabolic law. As the initial TiO 2 layer destroyed, the deuterium permeation flux increases. After the thickness of FeTiO 3 reaches a limit at corrosion time of 4000h, there exists a dynamic balance between the growth and the dissolution of FeTiO 3 , result in a small fluctuant deuterium permeation flux at corrosion periods of 5000–8000h. The deuterium permeation flux of the corrosion layer can be two orders of magnitude lower to that of Titanium alloy TA17 substrate. The formation process of corrosion layer and its effect on hydrogen permeation resistance are discussed in detail.