Coupling electrochemical permeation technique with respirometry: A novel approach for the simultaneous monitoring of corrosion-induced hydrogen formation and uptake

Corrosion-induced cathodic hydrogen evolution results in the formation of hydrogen, some of which enters the steel, possibly leading to critical failure of steel components. The relationship between hydrogen formation and uptake is still lacking in the literature. To address this, we developed a new technique coupling manometric respirometry and an electrochemical permeation technique to simultaneously monitor hydrogen formation and permeation. Galvanized press-hardened steel with ultimate tensile strength over 1500 MPa was tested under immersion corrosion conditions. Using combined electrochemical permeation and respirometry, hydrogen uptake efficiency in different phases of the corrosion process was determined to 6.7 % in average. Crucial role of coating cracks as locations of hydrogen entry in the beginning of the corrosion process was shown. Stable corrosion products gradually suppressed hydrogen entry. The novel electrochemical permeation and respirometry technique is a versatile approach for understanding corrosion-induced hydrogen formation and uptake.