Hydrogen absorption kinetics and mechanisms of rare earths (La, Ce, Pr, Nd, Tb, Dy) in the H2O surface reaction at room temperature

Kato, S.

doi:10.1016/j.jallcom.2005.04.092

Cited by 10 publications

(5 citation statements)

References 24 publications

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“…[39][40][41] In the present case, brittle hydride cracking is the most probable mechanism of hydrogen embrittlement. The argument for the proposed mechanism is based on the following factors: ͑i͒ strong affinity of rare earths for hydrogen, [10][11][12][13][14][15] ͑ii͒ previous research work carried out on the effect of hydrogen on corrosion of rare-earth alloy systems like Nd-Fe-B, 25,32,42 and ͑iii͒ correlation of the observed morphological features with hydrogen embrittlement mechanisms. 36,40 The strong affinity of rare earths with hydrogen was discussed above.…”

Section: Resultsmentioning

confidence: 99%

“…The interaction of hydrogen with rare-earth metal and alloys is well known. [10][11][12][13][14][15] Intermetallic compounds of rare earths with transition metals possess large hydrogen-absorbing capacities. 13,14 Hydrogen liberation normally accompanies corrosion in aqueous medium, which leads to hydrogen uptake in these compounds due to their strong affinity for hydrogen.…”

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confidence: 99%

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The Effect of Hydrogen on Corrosion of Tb[sub 0.3]Dy[sub 0.7]Fe[sub 1.92]

Sachdeva

Balasubramaniam

2008

J. Electrochem. Soc.

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The effect of hydrogen on the corrosion behavior of rare-earth-based magnetostrictive material Tb0.3Dy0.7Fe1.92 was studied after cathodic charging of hydrogen. The aqueous solutions used for understanding electrochemical behavior were 3.5% NaCl and 0.01 N Na2SO4 , in freely aerated and deaerated conditions. The severity of hydrogen attack in the presence of chloride ions increased with increasing hydrogen charging duration. Terraced and cleavagelike faceted features were evident on the surfaces after hydrogen charging and they were related to hydrogen embrittlement of the material. The destabilizing effect of chloride ions on the surface films, resulting in increased hydrogen uptake and consequent lowering of corrosion resistance, was verified by testing in chloride-free 0.01 N Na2SO4 environment in both freely aerated and deaerated conditions. The material was more tolerant to charged hydrogen in the absence of chloride ions. Protective surface film formation in 0.01 N Na2SO4 solution resulted in improved corrosion resistance of Terfenol-D compared to that in 3.5% NaCl solution.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

The Effect of Hydrogen on Corrosion of Tb[sub 0.3]Dy[sub 0.7]Fe[sub 1.92]

Sachdeva

Balasubramaniam

2008

J. Electrochem. Soc.

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“…The highest effect was produced by nitrogen ions . They also studied the irradiation effect that various ions have on the initial reaction rate of hydrogen absorption in electrode materials for Ni−H and NiM−H batteries based on rare earth based alloys . MmNi 3.48 Co 0.73 Mn 0.45 Al 0.34 (Mm=La 0.35 Ce 0.65 ), which is applied as the negative electrode of the Ni−H batteries and other hydrogen storage systems, was irradiated with H + , Ar + i K + ions of 350 keV energy, while fluence ranged from 10 14 ion/cm 2 to 10 17 ion/cm 2 .…”

Section: Experimental Approach To Destabilization Of Hydrogen‐storagementioning

confidence: 93%

“…The similar ion depth distribution is calculated also for Bi + ions. The absence of improvement in this case leads to conclusion that the nucleation and growth of hydride phase are not only influenced by the vacancies acting as the H trapping sites but also by the ions remaining in or near the formed defects since La and Ce tend to form stable hydrides . High concentrations of the vacancies near the alloy surface accelerate also the oxidation and alloy reaction with air moisture, so the alkaline treatment leads to penetration of alkaline atoms in the freshly formed surface oxide layers and reduction in the work function of surface electrons, resulting in the improvement of H 2 O dissociation and consequently hydrogenation ,.…”

Section: Experimental Approach To Destabilization Of Hydrogen‐storagementioning

confidence: 95%

“…Ion irradiation method found a significant application in the structural destabilization of materials for solid state hydrogen storage ,. This way it is possible to introduce a well‐defined concentration of defects (vacancies and dislocations) in the surface and subsurface layer of material ,.…”

Section: Experimental Approach To Destabilization Of Hydrogen‐storagementioning

confidence: 95%

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Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

Novaković

Kurko

et al. 2019

ChemPhysChem

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This review deals with the destabilization methods for improvement of storage properties of metal hydrides. Both theoretical and experimental approaches were used to point out the influence of various types of defects on structure and stability of hydrides. As a case study, Mg, and Ni based hydrides has been investigated. Theoretical studies, mainly carried out within various implementations of DFT, are a powerful tool to study mostly MgH 2 based materials. By providing an insight on metalhydrogen bonding that governs both thermodynamics and hydrogen kinetics, they allow us to describe phenomena to which experimental methods have a limited access or do not have it at all: to follow the hydrogen sorption reaction on a specific metal surface and hydrogen induced phase transformations, to describe structure of phase boundaries or to explain the impact of defects or various additives on MgH 2 stability and hydrogen sorption kinetics. In several cases theoretical calculations reveal themselves as being able to predict new properties of materials, including the ways to modify Mg or MgH 2 that would lead to better characteristics in terms of hydrogen storage. The influence of ion irradiation and mechanical milling with and without additives has been discussed. Ion irradiation is the way to introduce a well-defined concentration of defects (Frankel pairs) at the surface and subsurface layers of a material. Defects at the surface play the main role in sorption reaction since they enhance the dissociation of hydrogen. On the other hand, ball-milling introduce defects through the entire sample volume, refine the structure and thus decrease the path for hydrogen diffusion. Two Severe Plastic Deformation techniques were used to better understand the hydrogenation/dehydrogenation kinetics of Mg-and Mg 2 Nibased alloys: Equal-Angular-Channel-Pressing and Fast-Forging. Successive ECAP passes leads to refinement of the microstructure of AZ31 ingots and to instalment therein of high densities of defects. Depending on mode, number and temperature of ECAP passes, the H-sorption kinetics have been improved satisfactorily without any additive for mass H-storage applications considering the relative speed of the shaping procedure. A qualitative understanding of the kinetic advanced principles has been built. Fast-Forging was used for a "quasiinstantaneous" synthesis of Mg/Mg 2 Ni-based composites. Hydrogenation of the as-received almost bi-phased materials remains rather slow as generally observed elsewhere, whatever are multiple and different techniques used to deliver the composite alloys. However, our preliminary results suggest that a synergic hydrogenation / dehydrogenation process should assist hydrogen transfers from Mg/Mg 2 Ni on one side to MgH 2 / Mg 2 NiH 4 on the other side via the rather stable a-Mg 2 NiH 0.3 , acting as in-situ catalyser.

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Hydrogen Absorption Kinetics and Mechanisms of Rare Earths (La, Ce, Pr, Nd, Tb, Dy) in the H₂O Surface Reaction at Room Temperature.

Kato

2006

ChemInform

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Tb, Dy) in the H2O Surface Reaction at Room Temperature. -The reactivities of H2O and H2 gases with clean surfaces of the title rare earth metals are measured volumetrically at 298 K. The H2O reactivity is higher by factors of 10-1000 than the H2 reactivity, resulting in much higher rates of H absorption of the metals from water than from H 2 . The H atoms dissociated from the adsorbed H 2 O molecules dissolve into the metals to form the rare earth dihydride phase in much higher reaction rates than under H2 exposure. As the surface becomes covered with increasing amounts of hydroxide layers, the H atoms tend to associate to form H2 gas, resulting in marked H2 desorption. -(UCHIDA*, H.; KATO, S.; J.

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Hydrogen absorption kinetics and mechanisms of rare earths (La, Ce, Pr, Nd, Tb, Dy) in the H2O surface reaction at room temperature

Cited by 10 publications

References 24 publications

The Effect of Hydrogen on Corrosion of Tb[sub 0.3]Dy[sub 0.7]Fe[sub 1.92]

The Effect of Hydrogen on Corrosion of Tb[sub 0.3]Dy[sub 0.7]Fe[sub 1.92]

Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

Hydrogen Absorption Kinetics and Mechanisms of Rare Earths (La, Ce, Pr, Nd, Tb, Dy) in the H₂O Surface Reaction at Room Temperature.

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Hydrogen absorption kinetics and mechanisms of rare earths (La, Ce, Pr, Nd, Tb, Dy) in the H2O surface reaction at room temperature

Cited by 10 publications

References 24 publications

The Effect of Hydrogen on Corrosion of Tb[sub 0.3]Dy[sub 0.7]Fe[sub 1.92]

The Effect of Hydrogen on Corrosion of Tb[sub 0.3]Dy[sub 0.7]Fe[sub 1.92]

Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides