Synthesis and hydriding/dehydriding properties of Mg2Ni–AB (AB = TiNi or TiFe) nanocomposites
✍ Scribed by Z. Zlatanova; T. Spassov; G. Eggeler; M. Spassova
- Publisher
- Elsevier Science
- Year
- 2011
- Tongue
- English
- Weight
- 996 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0360-3199
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✦ Synopsis
Mg 2 NieTiFe and Mg 2 NieTiNi nanocomposites were prepared by milling for a short time of two preliminary milled to a nanocrystalline state hydrogen absorbing phases, Mg 2 Ni and TiFe or Mg 2 Ni and TiNi. The milling results in a sufficient density of contacts between the fine powder particles with different composition. The presence of a large amount of such inter-particles contacts leads to lowering of the initial temperature of the composites gas phase hydriding, as in the same time the temperature range of hydriding is enlarged, compared to the composites components.
On the grounds of the proved low temperature hydriding ( 200 C) of the nanocomposites, taking place with appropriate kinetics, the possibility for improved electrochemical hydriding was checked, exploiting the idea for charging Mg 2 Ni particles through the contacts with TiFe/TiNi. In this way we are supposed to achieve more complete electrochemical hydriding of the Mg 2 Ni particles, which are usually only superficially hydrogenated at room temperature, mainly due to the low diffusion coefficient of hydrogen in the Mg 2 Ni crystal lattice and corrosion processes in strong alkaline solutions. The achieved discharge capacity for the Mg 2 Ni-TiFe composite is essentially higher compared to that of the mechanical mixture of the two composite's components.