Background There is a need to develop quantitative, high-resolution hydrogen gas (H<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$_2$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>2</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>) permeation techniques to provide a better understanding of hydrogen-material interactions, from hydrogen uptake and diffusion to embrittlement. Objective This study aims to develop and validate a high-sensitivity H<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$_2$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>2</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation> permeation system, which is then leveraged to systematically quantify the influence of surface condition and key testing variables (surface oxides, residual gas impurities, pressure, and temperature) on hydrogen permeation. Methods A gas permeation system capable of operating at pressures up to 50 bar and temperatures up to 250 <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$^\circ $</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>C was developed, incorporating high-sensitivity mass spectrometric detection and controlled surface preparation protocols. Permeation transients were analysed in a model material (annealed pure Fe) to determine hydrogen diffusivity and permeability under systematically varied surface states, oxygen contents, pressures and temperatures. Results Surface oxides are shown to play a dominant role in controlling hydrogen permeation at room temperature. The presence of oxide layers can severely hinder or completely suppress hydrogen uptake, with measurable permeation requiring oxide removal via pickling and Pd coating on both surfaces, or activation through hydrogen-assisted reduction at elevated temperature. Residual oxygen present prior to hydrogen exposure further reduces permeability by modifying surface boundary conditions, indicating strongly surface-controlled kinetics. Under optimised surface conditions, hydrogen transport follows bulk diffusion-controlled behaviour, with steady-state flux obeying Sieverts’ law at 25 <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$^\circ $</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>C (1-5 bar) and diffusivity and permeability exhibiting Arrhenius behaviour between 25 and 150 <InlineEquation ID="IEq5"> <EquationSource Format="TEX">$^\circ $</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>C at 5 bar, indicating bulk diffusion-controlled transport. Conclusions The developed high-sensitivity permeation system resolves hydrogen fluxes as low as 1.98 <InlineEquation ID="IEq6"> <EquationSource Format="TEX">$\times $</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation> 10<InlineEquation ID="IEq7"> <EquationSource Format="TEX">$^{-9}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>-</mo> <mn>9</mn> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation> mol/(m<InlineEquation ID="IEq8"> <EquationSource Format="TEX">$^2$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mn>2</mn> </mmultiscripts> </math></EquationSource> </InlineEquation> <InlineEquation ID="IEq9"> <EquationSource Format="TEX">$\cdot $</EquationSource> <EquationSource Format="MATHML"><math> <mo>·</mo> </math></EquationSource> </InlineEquation>s) and provides a robust platform for investigating surface, mechanical and environmental effects on hydrogen permeation under realistic service conditions.

High-Sensitivity Hydrogen Gas Permeation: System Development, Sample Preparation, and Influence of Testing Variables

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2026年6月30日

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R. Li,
A. Zafra,
Z. D. Harris,
E. Martínez-Pañeda

摘要

Background

There is a need to develop quantitative, high-resolution hydrogen gas (H $_2$ $_{2}$ ) permeation techniques to provide a better understanding of hydrogen-material interactions, from hydrogen uptake and diffusion to embrittlement.

Objective

This study aims to develop and validate a high-sensitivity H $_2$ $_{2}$ permeation system, which is then leveraged to systematically quantify the influence of surface condition and key testing variables (surface oxides, residual gas impurities, pressure, and temperature) on hydrogen permeation.

Methods

A gas permeation system capable of operating at pressures up to 50 bar and temperatures up to 250 $^\circ $ $^{\circ}$ C was developed, incorporating high-sensitivity mass spectrometric detection and controlled surface preparation protocols. Permeation transients were analysed in a model material (annealed pure Fe) to determine hydrogen diffusivity and permeability under systematically varied surface states, oxygen contents, pressures and temperatures.

Results

Surface oxides are shown to play a dominant role in controlling hydrogen permeation at room temperature. The presence of oxide layers can severely hinder or completely suppress hydrogen uptake, with measurable permeation requiring oxide removal via pickling and Pd coating on both surfaces, or activation through hydrogen-assisted reduction at elevated temperature. Residual oxygen present prior to hydrogen exposure further reduces permeability by modifying surface boundary conditions, indicating strongly surface-controlled kinetics. Under optimised surface conditions, hydrogen transport follows bulk diffusion-controlled behaviour, with steady-state flux obeying Sieverts’ law at 25 $^\circ $ $^{\circ}$ C (1-5 bar) and diffusivity and permeability exhibiting Arrhenius behaviour between 25 and 150 $^\circ $ $^{\circ}$ C at 5 bar, indicating bulk diffusion-controlled transport.

Conclusions

The developed high-sensitivity permeation system resolves hydrogen fluxes as low as 1.98 $\times $ $\times$ 10 $^{-9}$ $^{- 9}$ mol/(m $^2$ $^{2}$ $\cdot $ $\cdot$ s) and provides a robust platform for investigating surface, mechanical and environmental effects on hydrogen permeation under realistic service conditions.