Simultaneous observations of the corrosion behavior of an Fe sheet and the associated hydrogen distribution therein employing a hydrogenochromic sensor

To understand hydrogen uptake into an Fe sheet due to corrosion, a hydrogenochromic sensor consisting of polyaniline and Ni layers was employed for the real-time visualization of hydrogen that entered an Fe sheet in a NaCl solution. The sensor was sensitive enough to visualize the hydrogen entry due to corrosion. Hydrogen entry into the Fe sheet was promoted on the dissolved area, while its entry was barely observed on the corrosion product-deposited area or oxygen reduction reaction site. The decrease in the solution pH and the exposure of the new Fe surface could be critical to the hydrogen uptake.

Automated summary

In this study, a hydrogenochromic sensor was used to visualize the real-time process of hydrogen entry into an Fe sheet during corrosion. The sensor successfully visualized the hydrogen entry, with promotion on the dissolved area and minimal observation on the corrosion product-deposited area or oxygen reduction reaction site. The decrease in solution pH and exposure of the new Fe surface were considered critical to hydrogen uptake.