Electrochemical Hydrogen Permeation Tests under Conventional Potentiostatic Hydrogen Charging Conditions for Hydrogen Embrittlement Study

Electrochemical hydrogen permeation tests were carried out under potentiostatic hydrogen charging conditions in various solutions, and the hydrogen entry behavior was compared with that of galvanostatic method. The relationship between hydrogen permeation current density and potential was similar in potentiostatic and galvanostatic methods and wide range of hydrogen concentration could be covered as well as galvanostatic method by varying NH4SCN content and potential. However, slight differences in hydrogen permeation current density and efficiency of hydrogen entry were seen between the methods, and the stability of hydrogen entry of potentiostatic method was slightly higher than that of galvanostatic method. In both methods, hydrogen permeation current density tended to increase with time in a NH4SCN containing solution suggesting that it is recommended to measure resulted hydrogen content by means of thermal desorption analysis for accuracy, though the relationship between hydrogen permeation current density and potential can be used as a rough standard.