Electrochemical methods for determining diffusion coefficient of hydrogen in steels

Abstract

Transport of atomic hydrogen in steels can be described by a complexmodel that takes into account
\ndiffusion laws (Fick’s laws) and the phenomena of hydrogen capture and release by different traps.
\nDifferent electrochemical methods for measuring the diffusion coefficient of atomic hydrogen are
\ncompared. Three metallurgical structures of low alloy 2.25Cr–1Mo steel and C–Mn microalloyed steel
\nare tested, the latter also with different degrees of plastic deformation. The test methodology that best
\nsimulates hydrogen diffusion through a lattice is the partial charge/discharge method. Within the limits
\nof the ‘material–environment’ combinations selected for this research, highly reproducible values of
\nthe diffusion coefficient are obtained, which decrease in the order of annealed,
\nquenched and tempered and quenched samples and also
\ndecrease as the plastic deformation increases.