Hydrogen diffusion in iron and ferritic stainless steel measured by electrochemical permeation experiments
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School of Engineering |
Master's thesis
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Date
2024-08-30
Department
Major/Subject
Mechanical Engineering
Mcode
Degree programme
Master's programme in Mechanical Engineering
Language
en
Pages
52
Series
Abstract
Hydrogen diffusion in cold rolled iron, annealed iron, and 430 stainless steel has been examined experimentally using the Devanathan-Stachurski method at 22◦C. The effective diffusion coefficient and the maximum hydrogen concentration have been calculated for all three materials using a variety of methods. The effective diffusion coefficient was calculated using five different methods commonly used in the literature the breakthrough method, the time lag method, and curve fitting with three different transient models. These methods gave different results, which demonstrates the limited ability of the unaltered Fick’s diffusion laws to describe hydrogen diffusion in real materials. The applicability of Fick’s laws to describe hydrogen movement increases as the effective diffusivity decreased. Additionally, experiments were done examining the impact of experimental methodology on the electrochemical hydrogen permeation experiments. The complex impact and interaction between many different parameters demonstrate the need for greater methodological uniformity within the hydrogen diffusion community. Surface roughness on the hydrogen oxidation surface was observed to have a strong impact on the diffusion transient, while the oxidation potential had a negligible impact, as long as the potential is within a reasonable range.Description
Supervisor
Vilaca, PedroThesis advisor
Huttunen-Saarivirta, ElinaPohjanne, Pekka
Keywords
hydrogen, permeation, diffusion, ferrite, Devanathan-Stachurski, hydrogen trapping