Effect of hydrogen sulfide and chloride on the passive film structures of stainless‐steel type 316 L.

The presence of hydrogen sulfide and chloride in oil and gas production environments can induce deterioration of the passive film, leading to pitting corrosion of stainless steel. In this research, localized behavior of stainless‐steel type 316 L was studied in highly hydrogen sulfide and chloride environment. The environmental condition was setting up using NACE TM0177 Solution A at different partial pressures of 0 bar, 3 bar and 15 bar of hydrogen sulfide, respectively. The results indicated that the presence of sulfides and chloride ions in test solution can decrease its corrosion resistance due to pitting corrosion attacking and promoting passive layer break down. Deterioration of passive film was analyzed using weight loss calculation, pit penetration analyses was done by infinite focus microscopy and surface morphology with the corrosion products were investigated by scanning electron microscope after 7 days immersion in test solution. Energy‐dispersive x‐ray results shows the presence of sulfur on the passive oxide layer at 3 bar and 15 bar conditions. Thus, the protection for these steels is undermined by hydrogen sulfide corrosion that affects on the passive films and altered its structure. [ABSTRACT FROM AUTHOR]