Corrosion Rate and Stress Corrosion Cracking Susceptibility of Copper in the Presence of Sulfides

This study evaluates corrosion behavior and stress corrosion cracking (SCC) susceptibility of high‑purity copper under anoxic sulfide‐containing conditions over a weakly acidic to near‐neutral pH range. Immersion tests, U‑bend tests, and slow strain rate tests (SSRT) are conducted in synthetic seawater at 80°C under various controlled H 2 S/N 2 atmospheres. Immersion tests show corrosion rates increase with H 2 S fraction while showing limited variation over 100 days for each H 2 S condition. U‑bend tests show intergranular corrosion. In SSRT, although opened intergranular attack near the fracture surfaces was observed under sulfide‐containing conditions, no clear evidence of SCC was identified. A diffusion‑controlled model assuming poorly protective Cu 2 S formation captures the overall trend of the immersion test data and is used to predict long‐term general corrosion. Sulfide flux above a literature‐based SCC threshold persists only briefly in a saturated buffer, even under conservative assumptions.