| 초록 |
Considering geographical characteristic of our country located in peninsula, nuclear power plants are situated in sea coast. For dry storage system near the nuclear power plant using air to cool down the used nuclear fuels, there is fair chance of exposure to chlorine environment. When weld stainless steel, which is a material used for dry storage canister, is exposed to corrosive environment, Stress Corrosion Cracking (SCC) may take place. To prevent SCC, we are presenting facile method to protect weld stainless steel from corrosive environment. Through simple anodization process, we can generate passive protective layer on the surface of substrate. This passive film is nanoporous oxide layer that blocks corrosive materials from substrate, plus its porous structure can relief the stress coming from oxide volume expansion so that it can also prevent cracking of oxide film. We used constant voltage of 80 V for 3600 sec. at 278K while anodizing. Electrolyte contained 0.1 mol NH4F + 0.1 mol H2O + Ethylene Glycol balanced. FESEM and EDX was used for evaluating the morphology. After that electrochemical analysis was performed to prove that nanoporous oxide layer improved corrosion resistance in an artificial seawater medium. We can expect further usefulness of this technique owing to its simplicity compared to traditional high temperature processing to prevent SCC. |
