Study of the Passivation Film on S32750 Super-Duplex Stainless Steel Exposed in a Simulated Marine Atmosphere

The corrosion behavior and passivation mechanism of S32750 super-duplex stainless steel exposed in a simulated marine atmosphere were studied using electrochemical methods, XPS SEM. Passivation local occurred on the metal surface when SDSS was atmospheric environment. film is composed two chromium-enriched layers. outer layer very thin at metal/atmosphere interface specimen with higher chromium content, whereas inner seems little depleted. layers had similar Fe components, Fe3+ oxide/hydroxide primary oxide film. contains CrO3, has Cr3+ as its oxide. Pitting exposure time exceeded 24 d, Cr content decreased. Therefore, for d exhibited best resistance.