Crevice corrosion of nickel superalloy in deaerated chloride/sulphate solution at 90°C

[摘要] Alloy 22 is a nickel base alloy highly resistant to all forms of corrosion. It was designed to resist to most aggressive environments for industrial applications. Electrochemical studies such as Potentiodynamic-Galvanostatic-Potentiostatic (PD-GS-PD) tests and Electrochemical Impedance Spectroscopy (EIS) and Scanning Electron Microscopy (SEM) observations were performed to determine the corrosion behaviour of alloy 22 (N06022). The effect of sulphate ion in chloride containing solutions at 90°C, were studied in this work under aggressive conditions where this material might be susceptible to crevice corrosion. The electrolyte solution, which consisted of 0.1M and 1M NaCl and different sulphate concentrations. It was observed that there were complete inhibitions of crevice corrosion for Rcrit=[SO4=]/[Cl-]=1 in the 0.1mol/L NaCl solutions and Rcrit=2 in the 1mol/L NaCl solutions. The corrosion rate obtained was about 0.1μm/year at 24 hours of immersion.

[发布机构] Universidad Industrial de Santander, Bucaramanga, Colombia^1;Comisión Nacional de Energía Atómica, Instituto Sábato, Buenos Aires, Argentina^2

[效力级别] 化学

[关键词] Aggressive environment;Corrosion behaviour;Electrochemical studies;Electrolyte solutions;Nickel base alloys;Nickel superalloy;Potentiodynamics;Sulphate concentrations