Changes in phase composition of Zr–Fe–V getter after hydriding and vacuum dehydriding cycles

Roupcová, Pavla; Schneeweiss, O.

doi:10.1016/j.jallcom.2009.11.147

Cited by 16 publications

(5 citation statements)

References 20 publications

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“…For the quantitative phase analysis, X'Pert HighScore plus software (version 2.2d) with Rietveld structural models based on the ICSD database was applied. 28,29 The crystallite sizes of tetragonal and monoclinic zirconia were calculated using the Scherrer equation.…”

Section: Methodsmentioning

confidence: 99%

“…The diffraction data was collected in the scanning angle (2θ) range of 10°–80° with a step size of 0.02° and counting time of 12 s at each step. For the quantitative phase analysis, X’Pert HighScore plus software (version 2.2d) with Rietveld structural models based on the ICSD database was applied. , The crystallite sizes of tetragonal and monoclinic zirconia were calculated using the Scherrer equation.…”

Section: Methodsmentioning

confidence: 99%

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Supporting Tungsten Oxide on Zirconia by Hydrothermal and Impregnation Methods and Its Use as a Catalyst To Reduce the Viscosity of Heavy Crude Oil

Wang

et al. 2012

Energy Fuels

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Tungsten oxide was supported on zirconia via hydrothermal and conventional impregnation methods and used as a catalyst to reduce the viscosity of heavy crude oil without the addition of water. Their properties and viscosity reduction activity were compared. X-ray diffraction and the Rietveld method were used to characterize the crystal structure and determine the phase composition. The properties of catalysts were also measured by N2 adsorption–desorption, differential scanning calorimetry, a Hammett indicator, and ammonia temperature-programmed desorption. Compared with the impregnation method, the hydrothermal method facilitates the formation of strong tungsten–zirconia interaction and promotes the diffusion of tungstate on zirconia, hence leading to better-dispersed tungsten oxide, as well as more tetragonal zirconia and acid sites. Under the reaction conditions of 220 °C, 6 h, and 2 MPa, the catalysts prepared via the hydrothermal method exhibit higher viscosity reduction activity than those prepared by impregnation. It is found the catalytic activity mainly depends on the acidity of the catalyst. The catalyst containing 20 wt % tungsten prepared by the hydrothermal method can attain a viscosity reduction ratio of 82.2% and reduce the viscosity of oil from 5.74 Pa s (50 °C) to 1.02 Pa s. Different from the widely used aquathermolysis technique, the presence of water is not required and the viscosity of the treated oil will not regress, even over long periods of time.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Supporting Tungsten Oxide on Zirconia by Hydrothermal and Impregnation Methods and Its Use as a Catalyst To Reduce the Viscosity of Heavy Crude Oil

Wang

et al. 2012

Energy Fuels

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“…The authors observed some hydrogen release up to 427 °C, attributed to some reversibility of Zr(V0.84Fe0.16)2 and Zr3(V0.84Fe0.16)3Ox but a large part of the hydrogen remains trapped in the highly stable -Zr phase, at least in this temperature range. The similar composition Zr70V24,6Fe5,4 was studied during hydrogen cycling by Roupcová and Schneeweiss [59]. The latter authors observed from both X-ray diffraction and Mössbauer spectroscopy that the hydrogen-free sample contains a cubic Laves phase and -Zr whereas the loaded material is made of the two hydrides ZrV2H3.6 and ZrH2.…”

Section: Zr-(ti)-v-fementioning

confidence: 87%

Intermetallic alloys as hydrogen getters

Cuevas

Latroche

2022

Journal of Alloys and Compounds

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“…3. As-prepared Zr-V-Fe powders are composed of pseudo binary intermetallic compound Zr(V 1-x Fe x ) 2 which is C15 Laves phase and α-Zr [14][15][16]. The amount of Ni on the surface of Zr-V-Fe powders increases significantly with the electroless plating time prolonged as shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…This indicates that the thickness of the Ni layer increases with the electroless plating time prolonged and 20 min is the proper electroless plating time to obtain Ni uniform coating.The getter powders were analyzed by X-ray diffraction to identify the phase and the patterns are shown in Fig.3. As-prepared Zr-V-Fe powders are composed of pseudo binary intermetallic compound Zr(V 1-x Fe x ) 2 which is C15 Laves phase and α-Zr[14][15][16]. The amount of Ni on the surface of Zr-V-Fe powders increases significantly with the electroless plating time prolonged as shown in Fig.3.…”

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confidence: 99%

Effects of Electroless Nickel on Hydrogen Absorption Properties of Zr-V-Fe Powders

Cui

et al. 2015

MSF

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Nickel coated Zr-V-Fe non-evaporable getter (NEG) powders were prepared using electroless plating. The microstructure and composition of the Ni-coated Zr-V-Fe powders were analyzed by XRD, SEM and EDS. The hydrogen absorption performance of Ni-coated Zr-V-Fe powders and as-prepared powders were analyzed by dynamic method after an activation at 300°C for 2 hours. The hydrogen absorption performance of Ni-coated Zr-V-Fe powders and as-prepared powders at 100°C, 200°C, 300°C, 400°C, and 500°C were also analyzed. The results indicated that Ni existed as crystalline phase. The Ni coating played an important role as a catalyst which favored the dissociation of hydrogen on surface and Ni lowers the hydrogen diffusion energy for the Zr-V-Fe powders. The hydrogen absorption kinetics of Ni-coated Zr-V-Fe powders was improved in comparison with that of the as-prepared powders, and a relatively higher absorption rate was exhibited.

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Changes in phase composition of Zr–Fe–V getter after hydriding and vacuum dehydriding cycles

Cited by 16 publications

References 20 publications

Supporting Tungsten Oxide on Zirconia by Hydrothermal and Impregnation Methods and Its Use as a Catalyst To Reduce the Viscosity of Heavy Crude Oil

Supporting Tungsten Oxide on Zirconia by Hydrothermal and Impregnation Methods and Its Use as a Catalyst To Reduce the Viscosity of Heavy Crude Oil

Intermetallic alloys as hydrogen getters

Effects of Electroless Nickel on Hydrogen Absorption Properties of Zr-V-Fe Powders

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