Effect of additional catalytic phases imposed by sintering on the hydrogen absorption behavior of AB2 type Zr-based alloys

Visintín, Arnaldo; Peretti, H.A.; Ruiz, Fabricio; Corso, H.L.; Triaca, Walter Enrique

doi:10.1016/j.jallcom.2006.02.070

Cited by 38 publications

(32 citation statements)

References 7 publications

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“…After annealing, the ZrNi secondary phase in the C15 alloy becomes undetectable. This reduction/diminishing of the secondary phase after annealing also occurs in the C14 AB 2 MH alloys [55,61,71,72]. In addition to C14 and TiNi, there is also a 5.2 wt % of C15 found in the C14 alloy since the alloy's e/a (6.82) is close to the e/a at the C14/C15 threshold for Zr/Ti ( ∼ =1.8 (6.91)) [24].…”

Section: X-ray Diffractometer Analysismentioning

confidence: 74%

“…While only the un-annealed C14 alloy was used for this comparative work, two versions of the C15 alloys were assessed: pristine (C15) and annealed alloys (C15A). Since the effects of annealing on the multi-phase C14-predominated AB 2 MH alloys have been well studied (elimination/reduction in secondary phase abundance results in reduction of synergetic effects, leading to deterioration of electrochemical properties) [55,61,71,72], only the impacts of annealing on the C15 AB 2 MH alloy will be verified in this work. ICP results of the three alloys (C14, C15, and C15A) are in excellent agreement with the corresponding design values.…”

Section: Methodsmentioning

confidence: 99%

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Comparison of C14- and C15-Predomiated AB2 Metal Hydride Alloys for Electrochemical Applications

Kim

Nei²,

Wan

et al. 2017

Batteries

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Abstract:Herein, we present a comparison of the electrochemical hydrogen-storage characteristics of two state-of-art Laves phase-based metal hydride alloys (Zr 21.5 (V and Cr) in the first composition results in an average electron density below the C14/C15 threshold ( e/a ∼ 6.9) and produces a C14-predominated structure, while the average electron density of the second composition is above the C14/C15 threshold and results in a C15-predominated structure. From a combination of variations in composition, main phase structure, and degree of homogeneity, the C14-predominated alloy exhibits higher storage capacities (in both the gaseous phase and electrochemical environment), a slower activation, inferior high-rate discharge, and low-temperature performances, and a better cycle stability compared to the C15-predominated alloy. The superiority in high-rate dischargeability in the C15-predominated alloy is mainly due to its larger reactive surface area. Annealing of the C15-predominated alloy eliminates the ZrNi secondary phase completely and changes the composition of the La-containing secondary phase. While the former change sacrifices the synergetic effects, and degrades the hydrogen storage performance, the latter may contribute to the unchanged surface catalytic ability, even with a reduction in total volume of metallic nickel clusters embedded in the activated surface oxide layer. In general, the C14-predominated alloy is more suitable for high-capacity and long cycle life applications, and the C15-predominated alloy can be used in areas requiring easy activation, and better high-rate and low-temperature performances.

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Section: X-ray Diffractometer Analysismentioning

confidence: 74%

Section: Methodsmentioning

confidence: 99%

Comparison of C14- and C15-Predomiated AB2 Metal Hydride Alloys for Electrochemical Applications

Kim

Nei²,

Wan

et al. 2017

Batteries

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“…In the present case, since Zr 7 Ni 10 concurrently presents with the C15 phase, the higher sorption performances cannot be solely related to the stacking faults itself. Moreover, there are reports suggesting that the Zr 7 Ni 10 offers catalytic activity for surface reactions and also acts as a medium for charge diffusion [30][31][32][33]. However, in spite of the presence of Zr 7 Ni 10 phase since few C15 compositions did not store hydrogen appreciably, it appears to be the distinct electronic structure of some composition of Zr-Mn-Ni makes the difference.…”

Section: Hydrogen Storage Characteristicsmentioning

confidence: 99%

Effect of Ni concentration on the structural and hydrogen storage characteristics of Zr–Mn based laves phase system

Kumar

Pukazhselvan

Tyagi

et al. 2013

Mater Renew Sustain Energy

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The present communication reports the hydrogen storage characteristics of ZrMn 2-x Ni x laves phase hydrides. It is observed that promising hydrogen storage materials can be tailored when ''x'' is in the range of 1.5 B x C 1. The materials formed within this range reversibly store *2 to *3 H/F.U. under manageable operating conditions. The composition ZrMn 0.5 Ni 1.5 is found to absorb and desorb hydrogen under room temperature. The other two compositions ZrMn 0.75 Ni 1.25 and ZrMnNi absorb *3.6 H/F.U. and release *3 and *3.2 H/F.U., respectively. In each case, almost half of the effective storage capacity of total can be reversibly stored within 5 s under room temperature. Therefore, the materials falling within the range of 1.5 B x C 1 are promising candidates for stationary device applications. The correlation between the compositions, structural-microstructural features and thermodynamic data are presented.

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“…[1][2][3][4][5][6][7] These catalytic phases were identified as mainly Zr 7 Ni 10 and Zr 9 Ni 11 , and in the case of ternary alloys of composition Zr(Cr x Ni 1-x ) 2 (with x varying around the value x = 0.5), the optimal amount of the phases was found to be about 20 pct by mass; the electrochemical properties of Zr-Ni-Cr alloys have been studied by Joubert et al, [3] and enhanced properties were attributed to the synergistic effect between Laves and Zr 7 Ni 10 phases. In recent work on more complex alloys, the beneficial effect of the microsegregated secondary phases on the discharge capacity of electrodes was demonstrated by comparing the performance of as-cast and annealed (without secondary phase) materials.…”

Section: Introductionmentioning

confidence: 99%

Examination of Multiphase (Zr,Ti)(V,Cr,Mn,Ni)2 Ni-MH Electrode Alloys: Part II. Solid-State Transformation of the Interdendritic B2 Phase

Bendersky

Wang

Boettinger

et al. 2010

Metall Mater Trans A

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Solidification microstructure of multicomponent (Zr,Ti)-Ni-(V,Cr,Mn,Co) alloys intended for use as negative electrodes in Ni-metal hydride (Ni-MH) batteries was studied in Part I of this series of articles. Part II of the series examines the complex internal structure of the interdendritic grains formed by solid-state transformation and believed to play an important role in the electrochemical charge/discharge characteristics of the overall alloy composition. By studying one alloy, Zr 21 Ti 12.5 V 10 Cr 5.5 Mn 5.1 Co 5.0 Ni 40.2 Al 0.5 Sn 0.3 , it is shown that the interdendritic grains solidify as a B2 (Ti,Zr) 44 (Ni,TM) 56 phase, and then undergo transformation to Zr 7 Ni 10 -type, Zr 9 Ni 11 -type, and martensitic phases. The transformations obey orientation relationships between the high-temperature B2 phase and the low-temperature Zr-Ni-type intermetallics, and consequently lead to a multivariant structure. The major orientation relationship for the orthorhombic Zr 7 Ni 10 type is [011] Zr7Ni10 //[001] B2 ; (100) Zr7Ni10 //(100) B2 . The orientation relationship for the tetragonal Zr 9 Ni 11 type is [001] Zr9Ni11 //[001] B2 ; (130) Zr9Ni11 //(100) B2 . Binary NiZr and ternary Ti-Ni-Zr phase diagrams were used to rationalize the formation of the observed domain structure.

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Effect of additional catalytic phases imposed by sintering on the hydrogen absorption behavior of AB2 type Zr-based alloys

Cited by 38 publications

References 7 publications

Comparison of C14- and C15-Predomiated AB2 Metal Hydride Alloys for Electrochemical Applications

Comparison of C14- and C15-Predomiated AB2 Metal Hydride Alloys for Electrochemical Applications

Effect of Ni concentration on the structural and hydrogen storage characteristics of Zr–Mn based laves phase system

Examination of Multiphase (Zr,Ti)(V,Cr,Mn,Ni)2 Ni-MH Electrode Alloys: Part II. Solid-State Transformation of the Interdendritic B2 Phase

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