Heat treatment influence on corrosion inhibitor performance for SMSS-13Cr in H2S-containing environment

A supermartensitic stainless steel (SMSS) was subjected to different heat treatment conditions to investigate the influence of microstructural changes on the corrosion inhibition performance of a gemini surfactant in sour environment. X-ray diffraction (XRD) and scanning electronic microscopy (SEM) characterization of the SMSS under as received, normalized, annealed, and quenched conditions were carried out before and after the electrochemical evaluation by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves (PPC) in the sour solution without and with the addition of gemini surfactant. The results of electrochemical measurements along with SEM observations revealed that the heat treatment conditions had no significant influence on the corrosion resistance in the sour solution without the inhibitor, whereas in the presence of inhibitor, the microstructure had a strong influence on adsorption of surfactant molecules on the metal surface, showing the better inhibition performance for the quenched condition. A lower retained austenite content in the microstructure seemed to have a harmful effect on the formation of a compact and more protective corrosion inhibitor film.