Pitting Corrosion Behavior of CUSTOM 450 Stainless Steel Using Electrochemical Characterization

Abstract

In this study, the electrochemical polarization tests were performed on tensioned and non-tensioned CUSTOM 450 specimens in a 3.5 wt% NaCl solution to investigate pitting potential and stable pit initiation time. A potentiodynamic test was conducted to determine the exact amount of pitting potentials. According to the potentiostatic tests, a relation between applied potential and the stable pit initiation time was obtained. Concerning this relation, stable pitting time can be predicted without experimental works. Optical microscopy was used to evaluate the shape of the pits. Tensile stress led the pit to experience the "pit to crack" step. The corrosion rate of samples was studied by the determination of mass loss. Mass loss measurements and current density-time curve in potentiostatic tests demonstrated the rate of pitting corrosion decreased as time passed. Finally, the depth of the pits was measured by the eddy current technique. The results showed that tensile stress facilitated deeper pit development.

Evaluation of pitting corrosion by dynamic speckle pattern analysis

“…CUSTOM 450 is sensitive to pitting corrosion in 3.5 wt% NaCl solution at the potential of 350 mV SCE , as described in the previous work 3 . The experiments are designed for the real-time monitoring of pitting corrosion at the maximum bending region.…”

“…To enhance the safety and decrease the cost of industrial systems, characterization of the evolution of the damage is essential 2 . Experimental methods, such as eddy current, electrochemical measurements 3 , optical microscopy, scanning electron microscopy (SEM), x-ray diffraction [4][5][6] , atomic force microscopy (AFM) 7 , and digital holography 8 can provide useful information about pitting corrosion. Here, we are going to examine the sample by dynamic speckle pattern analysis.…”

Dynamic speckle pattern analysis of pitting corrosion

“…Furthermore, the combination of corrosive environments with stress-concentrating factors exacerbates this issue, potentially leading to stress corrosion cracking (SCC). This highlights the imperative need for precise characterization and vigilant monitoring of pitting corrosion to bolster safety and reduce economic losses [1].…”

“…Acknowledging this limitation, our research introduces dynamic laser speckle analysis as a groundbreaking technique for the quantitative assessment of pitting corrosion. This method capitalizes on the dynamic speckle pattern, produced when coherent light interacts with a roughened sample, enabling the tracking of surface or internal structural changes over time [1,2]. Through the analysis of statistical variations in these speckle patterns, we achieve a more profound comprehension of the dynamics of pitting corrosion, encompassing its onset and progression.…”

Evaluation of pitting corrosion by dynamic speckle pattern analysis

“…Characterization of the progression of the damage is essential for increasing safety and minimizing the economic cost of the system 2 . Experimental methods, such as eddy current, electrochemical measurements 3 , optical microscopy, scanning electron microscopy (SEM), x-ray diffraction 4 – 6 , atomic force microscopy (AFM) 7 , and digital holography 8 can provide useful information about pitting corrosion. When a coherent light illuminates a rough sample, a dynamic speckle pattern forms such that any movement in either the exterior surface or interior structure of the sample under study can change that over time.…”