Inconel superalloys are employed in demanding components of different equipment. However, they can be exposed to atmospheric corrosion systems, such as marine and industrial environments. This research is focused on studying the localized corrosion susceptibility of Inconel 600, 690 and 718 exposed to H₂SO₄, 1 wt.% and 3.5 wt. % NaCl solutions, simulating marine and industrial atmospheres at 25 ± 0.5 °C. Localized corrosion behavior was characterized by electrochemical noise (EN) and cyclic potentiodynamic polarization (CPP) curves according to ASTM 6-199 ASTM G61 standards. The EN technique was analyzed through time series and analysis for chaotic systems, such as Hurst, Lyapunov and Husdorff coefficients, to determine the corrosion type of each system to reduce the uncertainty in common statistical analysis. The EN results show how Inconel superalloys tend to present localized attacks, being more notorious in NaCl. The application of specialized methods such as Hurst and Lyapunov helped to determine the corrosion system when alloys were characterized by EN. The results indicated that all superalloys exhibit positive hysteresis under CPP, indicating susceptibility to localized pitting corrosion.

In the aeronautics industry, high-strength steels such as AerMet 100 and 4340 are widely used in critical structural components that must withstand extreme operating environments. These materials possess high tensile strength, fracture toughness, and fatigue resistance. The aim of this investigation is to study the susceptibility to localized pitting corrosion of two aeronautics alloys, AerMet 100 and 4340, and their immersion in H₂SO₄, NaCl, and HCl solutions at room temperature, using electrochemical noise (EN) according to the ASTM ASTM-G199 standard. The EN signal was filtered by two different methods, and the polynomial method was employed to obtain Rn, LI, Kurtosis, Skewness, and the potential spectral density analysis (PSD). Results indicate that AerMet 100 exhibits lower corrosion rate—up to an order of magnitude lower than 4340. The resistance noise of 1599 Ω·cm² in NaCl is higher. This same behavior is replicated when analyzing the noise impedance response (Z_n). In conjunction with the analyses of PSD slope, it is reported that localized corrosion is the predominant mechanism in the evaluated environments.