Hydrogen intermetallic compounds

Quantitative predictions about the heats of formation of hydrides of intermetallic compounds have been discussed by Shilov etal. (1989) they studied reversible and irreversible transformations in intermetallic compound-hydrogen systems and observed that four basic types of PIT diagrams exist for these systems. 

Fig. 29. Synergetic effects with intermetallic compounds. Hydrogen evolution in 1 M KOH at 30 °C on (1) Ni, (2) La, and (3) LaNis. (MOE = mercury oxide electrode). Adapted from ref. 226, by permission of Elsevier Sequoia.

Tarasov B.P., Fokin V.N., Moravsky A.P., Shul ga Yu.M. Transformations in fullerene-intermetallic compound-hydrogen systems // Zhum. neorg. khimii. 1997. Vol. 42. P. 920. 

Flanagan, T.B., Oates, W.A. (1992) Thermodynamics of Intermetallic Compound - Hydrogen Systems. In Intermetallic Compound - Hydrogen , Berlin, Springer V.l, 49-85. 

Oates, W.A. and Flanagan, T.B. (1983) On the origin of increasing hydrogen pressure in the two-solid phase regions of intermetallic compound - hydrogen... 

Jacob, I. and Shaltiel, D., The Influence of A1 on the Hydrogen Sorption Properties of Intermetallic Compounds, "Hydrogen Energy Systems", Proc. 2nd World Hydrogen Energy Conf., 1978, Zurich, Pergamon Press, 3, 1689. 

E. L. Schlapback, ed.. Hydrogen in Intermetallic Compounds, Spriager-Vedag, Berlin, 1988, Chapt. 5, pp. 197—237. 

Intermetallic compounds of zirconium with kon, cobalt, and manganese absorb and desorb considerable amounts of hydrogen, up to ZrMri2 [68417-38-9] (128) and ZrV2H 2 [63440-37-9] (129). These and other zirconium intermetallic compounds are being extensively studied for possible hydrogen storage appHcations (130). 

In order for an intermetallic compound to react directly and reversibly with hydrogen to form a distinct hydride phase, it is necessary that at least one of the metal components be capable of reacting directly and reversibly with hydrogen to form a stable binary hydride. 

J T. B. Flanagan, W. A. Oates, in Hydrogen in Intermetallic Compounds (Ed. L. Schlap-bach), Topics in Applied Pshysics, No. 63, Springer Verlag, New York, 1988, p. 49. 

Several preparative methods do not use elemental mixtures. Group IIA-Pt intermetallic compounds have been prepared by reacting platinum metal with the group-IIA oxide under hydrogen or ammonia at 900-1200 C. Beryllium metal reacts with neptunium fluoride under vacuum at 1100-1200°C to form BC 3Np. 

Sandrock, G., S. Suda, and L. Schlapbach, Hydrogen in Intermetallic Compounds II. Surface and Dynamic Properties, Applications, in L. Schlapbach, Ed., Springer, Berlin, 1992, p. 179. 

Schlapbach, L. (ed.), Hydrogen in intermetallic compounds II. Surface and dynamic properties, applications, Topics Appl. Phys. 67, Springer, Berlin, 67,15-95, 1992. 

Buschow, K.H.J. (1984) Hydrogen absorption in intermetallic compounds. In Handbook on the Physics and Chemistry of Rare Earths, eds. Gschneidner Jr., K.A., and Eyring, L. (North-Holland, Amsterdam), Vol. 6, p. 1. 

The intermetallic compounds CePd3 and ZrPd3 exhibited higher selectivity for butene formation than Pd. On Pd the hydrogen and butadiene are adsorbed on similar sites, whereas on the intermetallic compounds different sites may be involved in these adsorption processes44. 

Metals, intermetallic compounds, and alloys generally react with hydrogen and form mainly solid metal-hydrogen compounds (MH ). Hydrides exist as ionic, polymeric covalent, volatile covalent and metallic hydrides. Hydrogen reacts at elevated temperatrrres with many transition metals and their alloys to form hydrides. Many of the MH show large deviations from ideal stoichiometry (n= 1, 2, 3) and can exist as multiphase systems. 

X.L. Yeh, K. Samwer, W.L. Johnson, Formation of an amorphous metallic hydride by reaction of hydrogen with crystalline intermetallic compounds - a new method of synthesizing metallic glasses, Appl. Phys. Lett. 42 (1983) 242-244. 

J.H.N. van Vucht, F.A. Kuijpers, H.C.A.M. Bruning, Reversible room-temperature absorption of large quantities of hydrogen by intermetallic compounds, Philips Res. Repts. 25 (1970) 133-140. 

A. Pebler, E.A. Gulbransen, Thermochemical and structural aspects of the reaction of hydrogen with alloys and intermetallic compounds of zirconium, Electrochem. Techn. 4 (1966) 211-215. 

Guenee et al. [169] synthesized by ingot metallurgy ternary intermetallic compounds LaNi Mg and NdNi Mg having the cubic MgCu Sn crystal structure. They can absorb reversibly up to four hydrogen atoms per formula unit at 7-8 bar and 50°C. The hydrides are stable at room temperature but desorb quite rapidly at 80°C in vacuum. In air, they decompose by catalytic water formation. 

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