Electrochemical hydrogen permeation on steel sheets with in situ electrodeposition of a Pd layer at the exit side

Electrochemical hydrogen permeation experiments were performed on Ti-microalloyed steel sheets. The input side was polarized as a cathode in a solution containing H2SO4 and NaAsO2, while the solution at the exit side contained a concentrated NaOH solution with a minor amount of Pd(NO3)2. The presence of the palladium compound in the exit solution made it unnecessary to deposit an electrocatalytic Pd layer prior to the permeation experiments. Multistep permeation curves were recorded and the apparent diffusion coefficient of hydrogen, as calculated from the second breakthrough time, proved to be reproducible.