scholarly journals Effect of Mg-Based of Multi-Layered Structure on Hydrogen Desorption Properties

2019 ◽  
Vol 804 ◽  
pp. 35-40
Author(s):  
Ning Ning Zhou ◽  
Dong Ying Ju

This study proposed the new method of preparing Mg-based composite by mixed powder Ni and Ti onto the surface of pure Mg ingot. The prepared method caused that hydrogen absorbing phase Mg2Ni and catalytic phase NiTi generated and distributed regularly. The pure Mg ingot as the center and the powder Ni and Ti as cladding material on the surface were formed and sintered, in which the temperature range of generated alloy phase Mg2Ni and NiTi was confirmed at first; according to the temperature range, the size of Mg2Ni and NiTi crystal grains at 650°C and 850°C were analyzed and compared, respectively; The size of Mg2Ni alloy phase at the surface and center was calculated by comparing the atomic radius of Ni, Ti to confirm that Mg2Ni distributed on the surface due to the atom Ti replaced the atom Ni in Mg2Ni to generate the alloy phase NiTi; the capacity of the hydrogen desorption reached 4wt% within 5min. The disadvantages that easy to chalking and difficult to activate in the conventional method were avoided and achieved the application of the multilayer composite material in hydrogen storage field.

2014 ◽  
Vol 29 (12) ◽  
pp. 1241
Author(s):  
ZHANG Guo-Fang ◽  
ZHANG Yang-Huan ◽  
LIU Zhuo-Cheng ◽  
XU Jian-Yi ◽  
ZHANG Yin

2020 ◽  
Vol 9 (6) ◽  
pp. 759-768
Author(s):  
Yunhui Niu ◽  
Shuai Fu ◽  
Kuibao Zhang ◽  
Bo Dai ◽  
Haibin Zhang ◽  
...  

AbstractThe synthesis, microstructure, and properties of high purity dense bulk Mo2TiAlC2 ceramics were studied. High purity Mo2TiAlC2 powder was synthesized at 1873 K starting from Mo, Ti, Al, and graphite powders with a molar ratio of 2:1:1.25:2. The synthesis mechanism of Mo2TiAlC2 was explored by analyzing the compositions of samples sintered at different temperatures. It was found that the Mo2TiAlC2 phase was formed from the reaction among Mo3Al2C, Mo2C, TiC, and C. Dense Mo2TiAlC2 bulk sample was prepared by spark plasma sintering (SPS) at 1673 K under a pressure of 40 MPa. The relative density of the dense sample was 98.3%. The mean grain size was 3.5 μm in length and 1.5 μm in width. The typical layered structure could be clearly observed. The electrical conductivity of Mo2TiAlC2 ceramic measured at the temperature range of 2–300 K decreased from 0.95 × 106 to 0.77 × 106 Ω–1·m–1. Thermal conductivity measured at the temperature range of 300–1273 K decreased from 8.0 to 6.4 W·(m·K)–1. The thermal expansion coefficient (TEC) of Mo2TiAlC2 measured at the temperature of 350–1100 K was calculated as 9.0 × 10–6 K–1. Additionally, the layered structure and fine grain size benefited for excellent mechanical properties of low intrinsic Vickers hardness of 5.2 GPa, high flexural strength of 407.9 MPa, high fracture toughness of 6.5 MPa·m1/2, and high compressive strength of 1079 MPa. Even at the indentation load of 300 N, the residual flexural strength could hold 84% of the value of undamaged one, indicating remarkable damage tolerance. Furthermore, it was confirmed that Mo2TiAlC2 ceramic had a good oxidation resistance below 1200 K in the air.


2021 ◽  
Vol 9 (13) ◽  
pp. 8341-8349
Author(s):  
Jiahe Zang ◽  
Shaofei Wang ◽  
Rongrun Hu ◽  
Han Man ◽  
Jichao Zhang ◽  
...  

A bimetallic oxide Ni3(VO4)2 has been synthesized to catalyze the hydrogen storage reaction of MgH2. The formation of the Mg2Ni alloy and the kinetic modulation of V results in a dehydrogenation temperature of 210 °C. The NiV2O4 intermediate active species is also detected.


2012 ◽  
Vol 586 ◽  
pp. 50-57
Author(s):  
Yang Huan Zhang ◽  
Tai Yang ◽  
Hong Wei Shang ◽  
Guo Fang Zhang ◽  
Xia Li ◽  
...  

In order to obtain a nanocrystalline and amorphous structure, the Mg20Ni8M2 (M=Cu, Co) hydrogen storage alloys were fabricated by the melt spinning technology. The microstructures of the alloys were characterized by XRD, SEM and HRTEM. The effects of the melt spinning on the hydriding and dehydriding kinetics of the alloys were investigated. The results indicate that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure even if the limited spinning rate is applied, while the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure as the spinning rate grows to 30 m/s, suggesting that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The melt spinning remarkably improves the gaseous hydriding and dehydriding kinetics of the alloys. As the spinning rate grows from 0 (As-cast was defined as the spinning rate of 0 m/s) to 30 m/s, the hydrogen absorption saturation ratio ( ) is enhanced from 56.72% to 92.74% for the (M=Cu) alloy and from 80.43% to 94.38% for the (M=Co) alloy. The hydrogen desorption ratio ( ) is raised from14.89% to 40.37% for the (M=Cu) alloy and from 24.52% to 51.67% for the (M=Co) alloy.


2011 ◽  
Vol 37 (7) ◽  
pp. 746-753 ◽  
Author(s):  
P. B. Somayajulu Rallapalli ◽  
Manoj C. Raj ◽  
Dinesh V. Patil ◽  
K. P. Prasanth ◽  
Rajesh S. Somani ◽  
...  

2004 ◽  
Vol 837 ◽  
Author(s):  
M. W. Zandbergen ◽  
S. W. H. Eijt ◽  
W. J. Legerstee ◽  
H. Schut ◽  
V. L. Svetchnikov

ABSTRACTThe hydrogen storage properties of nanostructured Mg and MgH2 thin films were studied as created by Ar and Ar+H2 plasma sputter deposition. Columnar structures with typical widths of ∼120 nm are observed with their long columnar axis extending throughout the thickness of the films. Applying substrate bias voltages during deposition results in narrower columns. A concomitant reduction in hydrogen desorption temperature from 400 °C to 360 °C is observed. Capping the Mg films with a ∼100 nm thin Pd layer leads to significantly reduced hydrogen desorption temperatures of ∼200 °C induced by the catalytic activity of the Pd cap layer. Also, hydrogen permeation of the films is strongly improved. The rate-determining factor is found to be the dissociation of the hydrogen molecules. Optimum hydrogen loading conditions of the Pd/Mg films were obtained just above ∼200 °C at hydrogen pressures of 0.25–1.0 MPa, resulting in hydrogen storage capacities in the range of 4–7 wt%.


2020 ◽  
Vol 4 (2) ◽  
pp. 691-699 ◽  
Author(s):  
Ekaterina Anikina ◽  
Amitava Banerjee ◽  
Valery Beskachko ◽  
Rajeev Ahuja

Low dimensions for hydrogen storage media: exceeding U.S. DOE uptake target on Li-functionalized carbyne with hydrogen binding energies needed for good cyclability.


2013 ◽  
Vol 807-809 ◽  
pp. 2707-2712 ◽  
Author(s):  
Shi Jian Yan ◽  
Xin Wei Zou ◽  
Min Gang Zhang

LaNi5-xwt%Mg hydrogen storage alloys with different Mg content were made from pure La, Mg and Ni metal powder by mechanical alloying, selecting appropriate ball-milling parameters in 0.4MPa hydrogen atmosphere. The characterizations for hydrogen storage alloy show that a multi-phase alloy composed of MgH2, LaH3, Mg2NiH4 and Ni was obtained, the alloy have two hydrogen desorption temperature range, and the alloy with 25wt% Mg content can desorb hydrogen up to 4.02wt%.


2001 ◽  
Vol 691 ◽  
Author(s):  
T. Sakakibara ◽  
Y. Takigawa ◽  
K. Kurosawa

ABSTRACTWe prepared a series of (AgBiTe2)1−x(Ag2Te)x(0≤×≤1) composite materials by melt and cool down [1]. The Hall coefficient and the electrical conductivity were measured by the standard van der Pauw technique over the temperature range from 93K to 283K from which the Hall carrier mobility was calculated. Ag2Te had the highest mobility while the mobility of AgBiTe2was the lowest of all samples at 283K. However the mobility of the (AgBiTe2)0.125(Ag2Te)0.875composite material was higher than the motility of Ag2Te below 243K. It seems that a small second phase dispersed in the matrix phase is effective against the increased mobility.


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