scholarly journals Crystallization Process, Structure and Hydrogen Absorption and Desorption Properties of MgxNi10 (x = 20.5-26.5) Alloys with Hypereutectic Composition

2021 ◽  
pp. X
Author(s):  
Xiaoping DONG ◽  
Yafang CHEN ◽  
Yurui MA ◽  
Xu LI
Keyword(s):  
Hydrogen Absorption ◽  
Crystallization Process ◽  
Hydrogen Desorption ◽  
Eutectic Structure ◽  
Absorption Capacity ◽  
Crystal Defects ◽  
Hydrogen Release ◽  
Hydrogen Saturation ◽  
Alloy Increase ◽  
Lower Temperature

We have analyzed crystallization process of the MgxNi10 (x = 20.5 – 26.5) alloys using phase diagram of Mg-Ni system. Their structure, atomic arrangement and crystal defects were tested by XRD, SEM and HRTEM, respectively. Hydrogenation and dehydrogenation behaviors were measured by pressure-composition-isotherm measurement. The results show that the crystallization processes of the MgxNi10 (x = 20.5 and 22.5) alloys are unlike those of the MgxNi10 (x = 24.5 and 26.5) alloys, but their room temperature microstructure all contain Mg2Ni and eutectic structure of Mg2Ni + α-Mg. The alloys are composed of Mg2Ni phase and α-Mg phase. The addition of Mg is beneficial to the formation of eutectic structure. The alloys have all good activation property. At a lower temperature, such as 200 and 250 °C, the hydrogen absorption rate and hydrogen saturation ratio are significantly lower than those of the alloy at the higher temperatures, such as 300 and 350 °C. At 350 °C, the hydrogen absorption capacity of the alloy increase and the hydrogen release efficiency of the alloy decreases with the increase of Mg content. The time of 90% of the amount of saturated hydrogen absorption and desorption of the alloys is not more than 10 and 2 minutes, respectively. The hydrogen desorption rate of the Mg22.5Ni10 alloy in the four investigated alloys is relatively large and up to 7.170 wt.%.min-1.

Hydriding and Dehydriding Characteristics of As-Spun Nanocrystalline and Amorphous Mg20Ni10-xMnx (x = 0-4) Alloys

2011 ◽  
Vol 347-353 ◽  
pp. 3420-3424
Author(s):  
Yang Huan Zhang ◽  
Xiao Gang Liu ◽  
Le Le Chen ◽  
Hui Ping Ren ◽  
Guo Fang Zhang ◽  
...  
Keyword(s):  
Amorphous Phase ◽  
Hydrogen Absorption ◽  
Melt Spinning ◽  
Hydrogen Desorption ◽  
Absorption Capacity ◽  
Desorption Kinetics ◽  
Nanocrystalline And Amorphous ◽  
Cast Alloys ◽  
Mn Content ◽  
Kinetics Of

The nanocrystalline and amorphous Mg2Ni-type Mg20Ni10-xMnx (x = 0, 1, 2, 3, 4) alloys were synthesized by melt-spinning technique. The structures of the as-cast and spun alloys were characterized by XRD, SEM and HRTEM. The hydrogen absorption and desorption kinetics of the alloys were measured. The results show that the substitution of Mn for Ni, instead of changing the major phase Mg2Ni, leads to the formation of Mg and MnNi phases. No amorphous phase is detected in the as-spun Mn-free alloy, but the as-spun alloys substituted by Mn display the presence of an amorphous phase, suggesting that the substitution of Mn for Ni enhances the glass forming ability of the Mg2Ni-type alloy. The hydrogen absorption capacity of the as-cast alloys first increases and then decreases with the variation of the amount of Mn substitution. The hydrogen desorption capacity of the alloys markedly increases with growing Mn content.

Hydrogen absorption of C14 Laves NiTiZr-NiVNb pseudo-binary alloys

2003 ◽  
Vol 801 ◽  
Author(s):  
Kazuhiro Ishikawa ◽  
Shintaro Noda ◽  
Kiyonori Suzuki ◽  
Kiyoshi Aoki
Keyword(s):  
Binary System ◽  
Hydrogen Absorption ◽  
Binary Alloys ◽  
Hydrogen Desorption ◽  
Absorption Capacity ◽  
The Other ◽  
Hydrogen Capacity ◽  
Desorption Temperature ◽  
Other Hand ◽  
Zr Alloy

ABSTRACTHydrogen absorption and desorption properties of C14 Laves NiTiZr-NiVNb and NiTiZr-NiVZr pseudo-binary alloys were investigated by using the Sieverts' apparatus, XRD and the hydrogen analyzer. The hydrogen capacity and the 50% hydrogen desorption temperature, Td, of the C14 Laves NiTiZr alloy is 1.5 (H/M) and 850 K, respectively. On the other hand, the hydrogen capacity of the C14 NiVNb alloy is 0.2 H/M. In the Ni(TiZr)1−x(VNb)x pseudo-binary system, the hydrogen capacity of the alloys is decreased with increasing x, but the 50% hydrogen desorption temperature is almost constant. The substitution of VNb reduces the hydrogen absorption capacity of the C14 Laves NiTiZr alloy. The hydrogen desorption temperature of Ni(Ti1−xVx)Zr alloy is reduced to 580 K without serious decrease of the hydrogen capacity with increasing x.

scholarly journals Absorption of Hydrogen in the HBond©9000 Metal Hydride Tank

2018 ◽  
Vol 6 (11) ◽  
pp. 15-20
Author(s):  
Lukas Toth ◽  
Tomas Brestovic ◽  
Natalia Jasminska
Keyword(s):  
Specific Heat ◽  
Present Article ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
Release Kinetics ◽  
Hydrogen Desorption ◽  
Intermetallic Alloy ◽  
Gas Pressure ◽  
Hydrogen Release ◽  
Absorption Of Hydrogen

The present article describes the measurements of hydrogen absorbed into an intermetallic alloy. The process of hydrogen absorption into a metal hydride tank is accompanied with generating heat that must be removed during the process. If the tank is not cooled, the gas pressure rapidly increases and even with a small amount of the stored hydrogen the pressure exceeds the permissible value. By contrast, during hydrogen desorption it is required to supply the same amount of specific heat to avoid a significant decrease in pressure which would result in a decrease in hydrogen release kinetics.  

Preparation and Hydrogen Storage Kinetics of Nanocrystalline and Amorphous Mg2Ni-Type Alloys

2013 ◽  
Vol 275-277 ◽  
pp. 1929-1933
Author(s):  
Yang Huan Zhang ◽  
Chen Zhao ◽  
Haitao Wang ◽  
Tai Yang ◽  
Hong Wei Shang ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Absorption ◽  
Melt Spinning ◽  
Hydrogen Desorption ◽  
Amorphous Structure ◽  
Absorption Capacity ◽  
Type Alloy ◽  
Cu Alloy ◽  
Nanocrystalline And Amorphous ◽  
Kinetics Of

In order to obtain a nanocrystalline and amorphous structure in the Mg2Ni-type alloy, the melt spinning technology has been used to prepare the Mg20Ni8M2 (M = Co, Cu) hydrogen storage alloys. The microstructures of the alloys were characterized by XRD, SEM and HRTEM. The effects of the melt spinning on the gaseous and electrochemical hydrogen storage kinetics of the alloys were investigated. The results indicate that the as-spun (M = Co) alloys display a nanocrystalline and amorphous structure as spinning rate grows to 20 m/s, while the as-spun (M = Cu) alloys hold an entire nanocrystalline structure even if a limited spinning rate is applied, suggesting that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The melt spinning remarkably ameliorates the gaseous hydriding and dehydriding kinetics of the alloys. As the spinning rate is raised from 0 (As-cast was defined as the spinning rate of 0 m/s) to 30 m/s, the hydrogen absorption saturation ratio ( ), a ratio of the hydrogen absorption capacity in 5 min to the saturated hydrogen absorption capacity, are enhanced from 80.43% to 94.38% for the (M = Co) alloy and from 56.72% to 92.74% for the (M = Cu) alloy. The hydrogen desorption ratio ( ), a ratio of the hydrogen desorption capacity in 20 min to the saturated hydrogen absorption capacity of the alloy, are increased from 24.52% to 51.67% for the (M = Co) alloy and from14.89% to 40.37% for the (M = Cu) alloy. Furthermore, the high rate discharge ability (HRD) and the hydrogen diffusion coefficient (D) of the alloys notably mount up with the growing of the spinning rate.

Pd–Ru electrodeposits with high hydrogen absorption capacity

2012 ◽  
Vol 20 ◽  
pp. 175-177 ◽  
Author(s):  
K. Hubkowska ◽  
M. Łukaszewski ◽  
A. Czerwiński
Keyword(s):  
Hydrogen Absorption ◽  
Absorption Capacity ◽  
High Hydrogen

Synthesis by High-Energy Ball Milling of MgH2-TiFe Composites for Hydrogen Storage

2017 ◽  
Vol 899 ◽  
pp. 13-18 ◽  
Author(s):  
Ricardo Mendes Leal Neto ◽  
Rafael de Araújo Silva ◽  
Ricardo Floriano ◽  
Graziele Cristina Seco Coutinho ◽  
Railson Bolsoni Falcão ◽  
...  
Keyword(s):  
Ball Milling ◽  
Hydrogen Absorption ◽  
Hydrogen Desorption ◽  
High Energy ◽  
Control Agent ◽  
High Energy Ball Milling ◽  
Absorption Kinetics ◽  
Particle Size Reduction ◽  
Milled Sample ◽  
Energy Ball

The aim of this work is to investigate the influence of some processes variables on the microstructure and hydrogen absorption kinetics of MgH2 - X wt.% TiFe composites. Samples were synthesized by high-energy ball milling in a planetary (X = 40, 50, 60) and shaker mill (X = 40) under high-purity argon atmosphere. Commercial MgH2 instead of Mg powder was used in order to reduce adherence on the vial and balls. TiFe powder was previously produced by ball milling a mixture of TiH2 and Fe powders followed by a reaction synthesis at 600oC. Milled composites samples were characterized by XRD and SEM analysis. Milling time was preliminary investigated (X = 40) in the planetary ball mill (6 to 36h). TiFe particle size reduction was shown to be difficult since they are surrounded by MgH2 matrix. Strong particle reduction was obtained by using a shaker mill only for 2 hours and adding cyclohexane as process control agent. No reaction between MgH2 and TiFe compound was observed in any milled sample. Hydrogen absorption kinetics measurements of the as-milled samples were conducted on an Sieverts' type apparatus at room temperature after hydrogen desorption at 350oC under vacuum. The best hydrogen kinetics (3 wt% at the first hour) was attained by the planetary milled sample (36 h). Higher hydrogen capacity was observed for the sample milled in the shaker mill (4.0 wt.%), but only after 13h.

scholarly journals Development of a Novel Method for the Fabrication of Nanostructured Zr(x)Ni(y) Catalyst to Enhance the Desorption Properties of MgH2

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 849
Author(s):  
Gracia Shokano ◽  
Zahir Dehouche ◽  
Basile Galey ◽  
Georgeta Postole
Keyword(s):  
Hydrogen Desorption ◽  
Milling Process ◽  
Hydrogen Release ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscope Analysis ◽  
Novel Method ◽  
Temperature Programmed ◽  
The Impact

The present work involves the development of a novel method for the fabrication of zirconium nickel (Zr(x)Ni(y)) alloy used as a nanocatalyst to improve the hydrogen storage properties of the Mg/MgH2 system. The catalyst was fabricated through the high-pressure reactor and activated under hydrogen prior to being mechanically milled with the MgH2 for 5 h under argon. The microstructure characterisation of the samples was determined via SEM-EDX (scanning electron microscope analysis–energy dispersive X-ray spectroscopy), XRD (X-ray diffraction) and FE-HRTEM (field emission high resolution transmission electron microscopy), and the desorption characteristic of the nanocomposite (10 wt.% Zr(x)Ni(y)–MgH2) was determined via TPD (temperature-programmed desorption). The nanostructured MgH2 powder milled with 10 wt.% of the activated Zr(x)Ni(y) based nanocatalyst resulted in a faster hydrogen release—5.9 H2-wt.% at onset temperature 210 °C/peak temperature 232 °C. The observed significant improvement in the hydrogen desorption properties was likely to be the result of the impact of the highly dispersed catalyst on the surface of the Mg/MgH2 system, the reduction in particle size during the ball milling process and/or the formation of Mg0.996Zr0.004 phase during the milling process.

The Effects of Oxidized and Oxide-Free Boron on the Mg-B-H Nanohydrides Transformation in the Nearly Nanosized Powders

2007 ◽  
Vol 128 ◽  
pp. 47-52 ◽  
Author(s):  
R.A. Varin ◽  
Ch. Chiu ◽  
Zbigniew S. Wronski ◽  
Andrzej Calka
Keyword(s):  
Hydrogen Desorption ◽  
Hydrogen Release ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Nanosized Powders ◽  
X Ray ◽  
Milled Sample ◽  
Heat Event ◽  
Reactive Mechanical Alloying ◽  
Type Apparatus

In this work oxidized and oxide-free amorphous boron (a-B) powder and elemental Mg were used in an attempt to directly synthesize the Mg(BH4)2 complex hydride by controlled reactive mechanical alloying (CRMA) under hydrogen in a magneto-mill up to 200h. The particle size was refined to the 100-200nm range. Nanocrystalline MgH2 (~6nm crystallite size) was formed within the particles when an oxidized a-B is used. In contrast, a mixture of MgB2 and an amorphous hydride MgHx was formed when an oxide-free a-B was used. Differential scanning calorimetry (DSC) test up to 500°C produced a single endothermic heat event at 357.7°C due to hydrogen desorption. In addition, desorption conducted in a Sieverts-type apparatus revealed ~1.4wt.% of hydrogen release. The X-ray diffraction pattern after DSC test of the 200h milled sample made with oxide-free boron showed the presence of MgB2.

scholarly journals Isotopic tracing of hydrogen transport and trapping in nuclear materials

2017 ◽  
Vol 375 (2098) ◽  
pp. 20160406 ◽  
Author(s):  
Jacques Chêne ◽  
Frantz Martin
Keyword(s):  
Hydrogen Embrittlement ◽  
Point Defects ◽  
Stress Corrosion Cracking ◽  
Hydrogen Absorption ◽  
Hydrogen Desorption ◽  
Nuclear Materials ◽  
Hydrogen Transport ◽  
Transport Mechanisms ◽  
Isotopic Tracing

Some illustrations of the use of deuterium or tritium for isotopic tracing of hydrogen absorption, transport and trapping in nuclear materials are presented. Isotopic tracing of hydrogen has been shown to be successful for the determination of the boundaries conditions for hydrogen desorption or absorption in a material exposed to a hydrogen source. Also, the unique capabilities of isotopic tracing and related techniques to characterize H interactions with point defects and dislocations acting as moving traps has been demonstrated. Such transport mechanisms are considered to play a major role in some stress corrosion cracking and hydrogen embrittlement mechanisms. This article is part of the themed issue ‘The challenges of hydrogen and metals’.

scholarly journals Hydrogen Absorption and Desorption in Steel by Electrolytic Charging

2006 ◽  
Vol 15-17 ◽  
pp. 816-821 ◽  
Author(s):  
Geert Mertens ◽  
Lode Duprez ◽  
Bruno C. De Cooman ◽  
Marc Verhaege
Keyword(s):  
Current Density ◽  
Hydrogen Absorption ◽  
Failure Mechanisms ◽  
Great Influence ◽  
Hydrogen Desorption ◽  
Cathodic Current Density ◽  
Cathodic Current ◽  
Charging Current ◽  
Current Densities ◽  
Profound Insight

The presence of hydrogen in steel decreases its toughness and formability leading to hydrogen embrittlement. To understand the failure mechanisms of steel due to the presence of hydrogen, a profound insight in the hydrogen household of the steel is needed. This includes a study of the solubility, the diffusion and the trapping of hydrogen. Next, the absorption and desorption behavior during and after electrolytic charging must be well determined. This was investigated in this research for steels with various types of traps, e.g. dislocations, microcracks, grain boundaries and precipitates such as TiC and Ti4C2S2. The samples were cathodically charged at three different current densities: 0.8mA/cm2; 8.3mA/cm2 and 62.5mA/cm2. It was noticed that the cathodic current density used for hydrogen loading had a great influence on the results. Observation of the samples by scanning electron microscopy (SEM) showed that at the highest current density major damage of the surface had occurred. Hence it was decided to study more systematically the influence of charging current density on the resulting surface aspect and on hydrogen absorption and desorption. The hydrogen charging kinetics, maximum hydrogen solubility and hydrogen desorption behavior have also been evaluated for the different current densities during charging.

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