Influence of Temperature on Hydrogen Penetration in Native Oxide and Iron at 1 bar H₂

Minli CHEN ^1,2,3, Dimitri MERCIER², Antoine SEYEUX², Sandrine ZANNA², Theodorus DE BRUIN¹, Gaurav R JOSHI³, Dominique COSTA² and Philippe MARCUS²

1. IFP Energies Nouvelles, Rueil-Malmaison (F)
2. Institut de Recherche de Chimie Paris, Chimie ParisTech-CNRS, Paris (F)
3. IFP Energies Nouvelles, Solaize, (F)

Hydrogen is set to play a crucial role in the energy transition to low-carbon energy systems. However, concerns persist regarding the structural integrity of hydrogen transport and storage infrastructure made from low alloy steel. Previous studies using gaseous and electrochemical permeation techniques have shown that native or thermally grown oxide layers can reduce hydrogen diffusion coefficients or prolong permeation times [1,2]. The durability and protective role of native oxides in mitigating hydrogen uptake and embrittlement remain unresolved, which this work seeks to address.

This study presents the influence of temperature on the penetration of hydrogen after removing the native oxide layer. A circuit system equipped with a hydrogen generator was used to expose low-carbon iron samples to hydrogen at 1 bar and a flow rate of 1 to 2 L/h. To remove the native oxide layer, samples were annealed at 700°C under a flow of H₂. After oxide reduction and subsequent exposure to H₂ at different temperatures, hydrogen penetration was analyzed using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Owing to the high sensitivity and in-depth profiling capabilities of ToF-SIMS, this method allows the study of iron oxide’s effect by comparing hydrogen distribution in subsurface layers of nanometric thickness of reduced or non-reduced samples at different temperatures. The results show that hydrogen penetration does not occur in samples with native iron oxide exposed to H₂ at room temperature, whereas oxide-reduced samples exhibit hydrogen uptake within a specific temperature range. The exposure temperature following oxide reduction is a crucial factor affecting hydrogen uptake.

[1] P. Tison, Influence de l’hydrogène sur le comportement des métaux, CEA-R-5240 (1), ISSN 0429-3460, 1984

[2] Zhang, T. et al., Effects of surface oxide films on hydrogen permeation and susceptibility to embrittlement of X80 steel under hydrogen atmosphere, International Journal of Hydrogen Energy, 43 (6), pp. 3353–3365, 2018