Application of an iridium complex for detecting hydrogen permeation through pure iron

Ajito, Saya; Hojo, Tomohiko; Koyama, Motomichi; Fujita, Ken‐ichi; Akiyama, Eiji

doi:10.1016/j.ijhydene.2020.06.113

Cited by 15 publications

(7 citation statements)

References 29 publications

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“…Currently, hydrogen embrittlement is one of the most important obstacles to using high-strength steels for corrosive environments and hydrogen-energy-related infrastructure. Therefore, hydrogen mapping techniques are indispensable to establishing a microstructure-design strategy for next-generation high-strength metallic materials. , Damage quantification coupled with microstructure, strain, and element mappings is expected to reveal the underlying role of plasticity in the microdamage evolution in advanced high-strength metallic materials.…”

Section: Discussionmentioning

confidence: 99%

Quantification and Characterization of Microdamage Resistance in Metals for Designing High-Strength Ductile Microstructures

Koyama

2021

Acc. Mater. Res.

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Conspectus Fractures in metallic materials such as ductile austenitic, ferritic, and dual-phase steels often occur after significant plastic deformation. The dislocation-driven plasticity enhances the microscopic stress concentration and induces vacancies (e.g., by the jogged screw dislocation motion), resulting in microstructure-scale cracks and voids at specific crystallographic planes or microstructure boundaries. (Hereafter, cracks and voids are referred to as damage.) In addition, plasticity plays important roles in microscopic damage growth in terms of damage tip blunting and coalescence. In fact, plasticity-related damage evolution in various fracture phenomena such as metal fatigue and hydrogen embrittlement still contains many uncertainties, particularly in high-strength materials containing fine and complex microstructures. Therefore, microscopy-based damage quantification and characterization are required for designing damage-resistant microstructures. In this context, because damage evolution is a multiscale phenomenon from atomistic to over millimeter scales, the target size of damage in the measurements is important to realize reliable analyses. The intrinsic origin of damage evolution is an atomistic/nanometer scale phenomenon, which requires transmission electron microscopy for its analysis. However, from mechanical viewpoints, revealing damage nucleation behavior is not necessary, because general mechanical analyses are performed for oversubmicrometer-sized damages that can be observed by optical microscopy and scanning electron microscopy. Hence, submicrometer/micrometer-sized damage is the major target in this damage quantification. As a post-mortem analysis method, the damage area fraction, the number of damages, the damage size, and the damage shape at various plastic strains can be quantified by observing micrometer-sized damages. In the case of monotonic tensile deformation, the number density of damages plotted against strain indicate the damage initiation probability. In addition, when damages stop growing, a strain range where the average damage size remains nearly constant appears. The strain range quantitatively indicates damage arrestability. For instance, dual-phase steel consisting of soft and hard body-centered cubic phases clearly shows three strain-dependent damage evolution regimes: (1) damage incubation regime (no damage appears), (2) damage arrest regime (damage initiates, but stops growing immediately), and (3) damage growth regime. Hydrogen uptake increases damage initiation probability and decreases damage arrestability. Specifically, a comparison of the quantified damage parameters between specimens with and without hydrogen revealed that large amounts of hydrogen in the dual-phase steel degrades the resistance to microscopic damage growth, which critically decreases the macroscopic ductility. In this case, the damage arrestability (damage growth resistance) is more important than crack initiation resistance, which is dependent on the dislocation-driven stress accommodatio...

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Section: Discussionmentioning

confidence: 99%

Quantification and Characterization of Microdamage Resistance in Metals for Designing High-Strength Ductile Microstructures

Koyama

2021

Acc. Mater. Res.

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“…The hydrogen diffusion coefficient, D H for Fe was reported to be 1.1 × 10 − 5 cm 2 s − 1 . 37) According to the calculation of the breakthrough time, the i per should increase within ca. 4 min after an NaCl droplet is placed on the Fe surface.…”

Section: Changes In R P and I Per For Fe During Drying Of Anmentioning

confidence: 99%

Simultaneous Measurements of Polarization Resistance and Hydrogen Permeation Current of Iron in an Aqueous NaCl Droplet

et al. 2021

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In this study, a Kelvin probe (KP) technique combined with the Devanathan-Stachurski electrochemical hydrogen permeation method was applied for simultaneous measurements of polarization resistance and hydrogen permeation current for iron to clarify the hydrogen uptake mechanism during drying of an NaCl droplet. The reciprocal of the polarization resistance, which is an index of the corrosion rate, the hydrogen permeation current, and the corrosion potential under the droplet were successfully measured. The corrosion potential decreased, and the hydrogen permeation current increased, after the NaCl droplet had been applied to the iron surface. The reciprocal of the corrosion resistance increased gradually during the drying of the droplet with increasing the corroded areas on the iron. The hydrogen permeation current decayed with the shift in the corrosion potential toward the noble side during the drying stage, before the droplet dried up completely. The hydrogen permeation current mainly followed the change in the corrosion potential. The hydrogen uptake mechanism of iron during corrosion is discussed in detail based on the corrosion potential, corrosion rate and hydrogen permeation behavior.

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“…[16][17][18][19][20][21][22][23][24] While the SKP and KPFM are powerful tools for the real-time mapping of hydrogen uptake experimentally, more convenient and simpler methods are required for the application in atmospheric environments. 25) We reported an approach to detecting the distribution of hydrogen uptake into pure iron using a WO 3 thin film. 26) WO 3 has the electrochromic property, and its optical property changed by the formation of H x WO 3 .…”

Section: Introductionmentioning

confidence: 99%

Improved Responsivity and Sensitivity of Hydrogen Mapping Technique in Pure Iron Using WO<sub>3</sub> Thin Film by Control of Pd Intermediate Layer

Sugawara

Saito

2021

ISIJ Int.

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The objective in this study is to improve the responsivity and the sensitivity of the hydrogen mapping technique using the WO 3 thin film by the optimization of the Pd intermediate layer. Especially, the effect of the thickness of Pd on the responsivity and the sensitivity of the hydrogen detection during hydrogen charging was investigated. Pd and WO 3 thin films were coated on the detection side of the pure iron sheet by a magnetron sputtering system. No color change was observed on the hydrogen detection side of the specimens with the Pd intermediate layer more than 25 nm in thickness during the hydrogen detection test for 7.2 ks. The responsivity for the hydrogen mapping technique using WO 3 was essentially improved by decreasing the Pd thickness. In terms of the onset time of the average color change, the earliest response was obtained when the Pd thickness was 4 nm because of the uneven distribution of the color change in the case of the Pd thickness of 2.5 nm. The sensitivity for the hydrogen mapping technique using WO 3 was improved by decreasing the Pd thickness. Taking into account the responsivity, the sensitivity, and the spatial resolution comprehensively, the best thickness of the Pd intermediate layer seems to be 4 nm in this study.

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Application of an iridium complex for detecting hydrogen permeation through pure iron

Cited by 15 publications

References 29 publications

Quantification and Characterization of Microdamage Resistance in Metals for Designing High-Strength Ductile Microstructures

Quantification and Characterization of Microdamage Resistance in Metals for Designing High-Strength Ductile Microstructures

Simultaneous Measurements of Polarization Resistance and Hydrogen Permeation Current of Iron in an Aqueous NaCl Droplet

Improved Responsivity and Sensitivity of Hydrogen Mapping Technique in Pure Iron Using WO<sub>3</sub> Thin Film by Control of Pd Intermediate Layer

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