2003 Volume 52 Issue 10 Pages 545-553
It is important to examine the effect of corrosion products on the corrosion rate of carbon steel overpack container for the geological disposal of radioactive wastes. In order to understand the influence of Fe3O4 film as the corrosion product, the corrosion behavior of carbon steel with and without Fe3O4 film produced by oxidization in a concentrated alkali solution was examined. The result of immersion corrosion tests in compressed bentonite containing water showed that the corrosion of carbon steel was promoted by the self-reduction reaction of Fe3O4 film, and that the most stable corrosion product in the test environment was a mixture of FeCO3 and Fe2(OH)2CO3. Then, to reveal the effect of alloying elements on the corrosion of the steel in the test environment, several kinds of low alloy steel were prepared by adding various metallic elements to the steel. The corrosion resistance of the low alloy steels with and without Fe3O4 film was examined. The result showed the corrosion of the steels was suppressed by the addition of Cu, Ti, and Cr, independently of the existence of Fe3O4 film. Among them, Cu showed the highest suppression effect.
