Electrochemical Noise of SCC Inhibition of a Supermartensitic Stainless Steel in Sour Solution

Abstract

In this work, the inhibition effect of a non-ionic gemini surfactant, named bis(2-((2-palmitoamidoethyl)amino)ethyl)1H-imidazole4,5-dicarboxylate, on the stress corrosion cracking (SCC) behavior of a supermartensitic stainless steel (SMSS) was studied in sour environment. The slow strain rate stress tests (SSRT) results and fractographic analysis revealed that the corrosion inhibitor was able to inhibit the SCC process using a concentration above than 5ppm. At concentrations of 0 and 5 ppm, the steel showed a brittle fracture with susceptibility to SCC, whereas at concentrations of 25 and 100 ppm, the fracture was ductile, and the steel was practically immune to SCC. The EN measurements showed transients associated with pits and microcracks, which were confirmed by SEM examination. The EN analysis using the shot noise theory indicated that localized corrosion was the dominant corrosion process at the concentrations of inhibitor in which the SMSS was susceptible to SCC.