Hydrogen Laves phases

Abstract. The interaction of hydrogen with ZrMn2 Laves phase compound at pressure up to 60 atm and temperature range from 100 to 305 °C has been investigated using reaction calorimetry. The obtained results allow us to propose the existence of two hydride phase in the ZrMn2-H2 system. 

Shaltiel, D., Jacob, I., Davidov, D. (1977) Hydrogen absorption and desorption properties of AB2 Laves-phase pseudobinary compounds J.Less-common metals 53, 117-131. 

Keywords Laves phases, NbVCoD2.5, high gaseous pressure of hydrogen, neutron diffraction... 

In accordance with calculations have been established, that in solid solution hydrogen occupied all sites with A2B2 coordination, typical for Laves phases (1, k, hi, h2), but with different probability (table 4). Generally hydrogen atoms occupied 1 and k sites (in rate 4 1), and in h site the occupancy is less than one atom at elementary cell of hydride (0,84) and this occupancy decreasing until 0,6 with lowering of the hydrogen content. 

Shoemaker D.P., Shoemaker C.B. (1979) Concerning atomic sites and capacities for hydrogen absorption in the AB2 ffiauf-laves phases. Les-Common Met. 668, 43-58. 

Irodova A.V. (1980) Directional order (k=0) in hydrogen solid solution based on Cubic (C15) Laves phases. (Preprint IAE-3308/9), Moscow, 16. 

Scripov A.V. (2004) Hydrogen jump motion in Laves-phase hydrides two frequency scales. International Symposium on Metal-Hydrogen Systems, Crakow, Poland. 

Abstract. The interaction of hydrogen with nonstoichiometric Tio.9Zro.iMnL3Vo.5 Laves phase compound at pressure up to 60 atm and in temperature range from 150 to 190°C has been studied by means of calorimetric and P-X isotherm methods. The obtained results allow us to propose the existence of one hydride phase, 0-hydride, in the Ti0 9Zr0 jMnj 3V0 5 - H2 system in the temperature range 150-170°C. It has been found that temperature 190°C is close to critical temperature (182°C) above which hydride phases does not exist. 

Only rare-earth system (AB5-type) and zirconium-titanium-vanadium system (AB2 Laves phase-type) hydrogen storage alloys have been used as negative electrode materials for the commercial production of Ni-MH batteries [3, 7, 8], However, these materials have a low hydrogen storage capacity resulting in a low electrode energy density. 

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