Simultaneous In Situ Imaging of pH and Surface Roughening during the Progress of Crevice Corrosion of Stainless Steel

Stainless steel plays an important role in industry due to its anti-corrosion characteristic. It is known, however, that local corrosion can damage stainless steel under certain conditions. In this study, we developed a novel measurement system to observe crevice corrosion, which is a local corrosion that occurs inside a narrow gap. In addition to pH imaging inside the crevice, another imaging technique using an infrared light was combined to simultaneously visualize surface roughening of the test piece. According to experimental results, the lowering of local pH propagated inside the crevice, and after that, the surface roughening started and expanded due to propagation of corrosion. The real-time measurement of the pH distribution and the surface roughness can be a powerful tool to investigate the crevice corrosion.

Automated summary

Stainless steel is crucial in industry due to its resistance to corrosion. However, local corrosion can occur under specific conditions. In this study, a novel measurement system was developed to observe crevice corrosion, and real-time measurements of pH distribution and surface roughness were conducted using pH imaging and infrared light techniques. These measurements provide valuable insights into the propagation of crevice corrosion.