Control of electrochemical parameters for hydrogen permeation of CLF-1 steel

The electrochemical hydrogen permeation method is reliable for evaluating the intrinsic hydrogen permeation resistance due to its room-temperature operation. However, the control of electrochemical parameters for hydrogen permeation testing has rarely been reported. In this study, we discussed the effects of anode background current, cathode current density, and cycle times on the electrochemical permeation behavior of CLF-1 RAFM steel. Results show that the anode background current below 1 mu A can ensure the accuracy of the permeation test. There exists a diffusion delay for the first permeation loop of CLF-1 steel because of the hydrogen trap effect, which can be eliminated by annealing the steel at temperature of 740 C-degrees for 2h. For the second and third permeation loops of CLF-1 steel, a sample with a high cathode current density tends to have a high permeation signal because of corrosion. Plating a protective nickel film can reduce the corrosion impacts for the hydrogen permeation test. The effects of hydrogen traps and corrosion on the permeation behavior were discussed in detail. Our study provides a promising approach for hydrogen permeation testing and hydrogen trap detection at room temperature.