Dear Catalina Zurano,
Corrosion Vs. pH for SS316 is very complex. Others factors are also influenced on pH. Acidic attack on stainless steels is very complex and depends not just on the pH but what acid is present, whether the acid is weak or strong, the type of acid (non-oxidizing versus oxidizing), the temperature, and level of dissolved oxygen. At low pH Ferric chloride corrodes SS 316 stainless steel. This ferric chloride formed at low pH and that ferric chloride attack on Ni which is present in SS more nickel more corrosion. If the temperature considered then The corrosion rate of 316L SS increases with increasing pH in hydrogenated high temperature water at 300 °C. Higher pH reduces the stability of the oxide films and accelerates the dissolution process of the oxides. With increasing pH, the corrosion rate decreases, being highest at pH 4 and lowest at pH 9. The number and depth of pits increase with increasing Cl− concentration. From the results of cyclic polarization is inferred that the pitting potential, Epit is shifted to a more negative potential with increasing Cl− concentration and temperature and decreasing pH .At low pH, high Cl− content and stagnancy are the conditions most suitable for initiation and propagation of pitting in AISI 316L stainless steel.