Investigation of stress-enhanced surface reactivity on Alloy 800 using scanning electrochemical microscopy

Scanning electrochemical microscopy (SECM) was used to simultaneously investigate the impact of tensile and compression stress on reactivity of the same Alloy 800 sample in ferrocenemethanol solution containing thiosulfate. Strong surface reactivity was observed on the stressed regions. Both tensile (the exterior edge) and compressed (inner edge) regions showed higher reactivity than the region between these. Hence both tensile stress and compression stress increased the localized surface reactivity, indicating potential for acceleration of corrosion susceptibility of Alloy 800 under stress in thiosulfate-contained chemistries.