Hydrogen absorption and crevice corrosion behaviour of titanium grade-12 during exposure to irradiated brine at 150 degrees C

The corrosion of titanium grade-12 alloy in a brine containing a substantial concentration of magnesium has been studied. Two degradation modes have been considered: hydrogen-induced delayed failure, and crevice corrosion. The work was undertaken primarily to determine the rate of hydrogen adsorption by specimens exposed to hydrothermal brines that had been irradiated at 2 x 104 rad/h at 150 C. After six months' exposure, two of the twenty specimens showed severe corrosion, a deposit of titanium dioxide that had originated within the crevice underneath an aluminum spacer holding the sample. Further testing of creviced samples showed some degree of corrosion where the specimens were in contact. The corrosion progressed along the surface of the material but did not penetrate deeply. It appears that irradiation of the environment and the formation of oxidizing radiolysis products were not sufficient to maintain the metal in the crevice region in an oxidized, passive condition. Specimens from this test absorbed hydrogen at a low rate, and hydrogen pickup appeared to stop after six months