Structural and hydriding properties of the Mg_Ni_H system with nano- and/or amorphous structures

Synthesis of Nonstoichiometric Amorphous Mg-Based Alloy Electrodes by Mechanical Milling

“…Figure 2 shows the XRD patterns of the IM Mg 2 Ni alloy ballmilled with Ni powders in different ratios, indicating that homogenous amorphous MgNi and MgNi 1.14 were formed: Mg 2 Ni + 1.28 Ni j 2MgNi 1.14 . Orimo et al 13 reported that the high resolution TEM image and its diffraction pattern of compound Mg 2 Ni ballmilled with Ni powder (molar ratio: 1:1, e.g., Mg-50 atom % Ni, or MgNi) shows that an amorphous structure was obtained. The ballmilled alloys of the composition of Mg-33 atom % Ni, Mg-38 atom % Ni, and Mg-43 atom % Ni only have a nanostructure or a mixture of partial nanostructure and partial amorphous structure.…”

“…The ballmilled alloys of the composition of Mg-33 atom % Ni, Mg-38 atom % Ni, and Mg-43 atom % Ni only have a nanostructure or a mixture of partial nanostructure and partial amorphous structure. 13 This means that decreasing the Mg content may cause more difficulty in obtaining an amorphous structure for Mg-Ni alloys. Our result indicates that an amorphous structure can be obtained even if the nickel content is increased.…”

Morphologic, Structural, Steric, Energetic and Thermodynamic Studies of the Mechanical Alloy Mg50Ni45Ti5 for Hydrogen Storage

“…In fact, long-term of ball milling usually leads to the increase of the influence of grain boundaries and enhance the diffusion of hydrogen [5]. Furthermore, among the benefits of using ball -milling to prepare improved Mg-based materials, we find the ease of formation of several alloys [6][7][8][9][10] and hydride phases [7], the generation of fresh and highly reactive surfaces during the milling operation which intensify the hydrogen absorption rate [9] and the obtainment of Mg-based materials in the nanocrystalline or amorphous state, with various amounts of dislocations and special defects with high binding energy for hydrogen [8,11]. All the investigations suggest that the milled Mgalloys differ greatly in nature from the crystalline ones and the addition of Ni facilitates the absorption and the desorption of hydrogen [12] and decreases the hydrogen sorption temperature.…”

Hydrogen-Storage Properties and Structure Characterization of Melt-Spun and Annealed Mg-Ni-Nd Alloy

“…In addition, reducing the grains of the matrix is thought to be another efficient way to improve the reaction kinetics because it may enhance the inward transport of H atoms along the grain boundaries and thereby reduce the depth of the hydride layer. The effectiveness of refining the microstructures for improving the reaction kinetics has really been proved for Mg-based alloys fablicated by mechanical alloying 3,8,9) and melt-spinning. 4,10) The objective of the present study is firstly to examine the hydrogen-storage characteristics of a Mg-rich Mg-Ni alloy added with a small amount of Nd and subjected to melt-spinning and annealing, and secondly to characterize its microstructure by high-resolution transmission electron microscopy (HRTEM) and electron diffraction (ED) for discussing a possible H/D mechanism in the alloy.…”