Surface vs diffusion in TDS of hydrogen

Abstract

The paper addresses the numerical simulation of conditions in which the measurement of thermal desorption spectra of hydrogen (TDS) is carried out. Plane steel samples of 10 mm thickness were used as the specimens for simulation. The skin effect which is observed with standard hydrogen charging of samples was accounted for the initial conditions. The standard diffusion of hydrogen was simulated according to Fick's law. Solution of the Fick's equation is obtained by finite element methods using the developed code. The resulting solutions show that standard hydrogen charging can lead to the appearance of an additional TDS peak, even without taking into account the traps. New interpretation of the TDS method for hydrogen dissolved in a solid was suggested.