Intermetallic compound synthesis

N.N. Thadhani, Shock-Induced Chemical Synthesis of Intermetallic Compounds, in Shock Compression of Condensed Matter—1989 (edited by S.C. Schmidt, J.N. Johnson, and L.W. Davison), Elsevier Science, Amsterdam, 1990, pp. 503-510. 

Thadhani, N.N., Shock-Induced Chemical Synthesis of Intermetallic Compounds, presented at the American Physical Society Topical Conference on Shock Compression of Condensed Matter, Albuquerque, NM, August 14-17, 1989. 

In this chapter synthesis of zinc ferrites, intermetallic compounds, and metal-oxides. 

Kanatzidis MG, Pottgen R, Jeitschko W (2005) The metal flux a preparative tool for the exploration of intermetallic compounds. Angew Chem Int Ed 44 6996-7023 Trindade T, O Brien P, Pickett NL (2001) Nanocrystalline semiconductors Synthesis, properties, and perspectives. Chem Mater 13 3843-3858... 

Intermetallic compound formation may be observed as the result from the diffusion across an interface between the two solids. The transient formation of a liquid phase may aid the synthesis and densification processes. A further aid to the reaction speed and completeness may come from the non-negligible volatility of the component(s). An important factor influencing the feasibility of the reactions between mixed powders is represented by the heat of formation of the desired alloy the reaction will be easier if it is more exothermic. Heat must generally be supplied to start the reaction but then an exothermic reaction can become self-sustaining. Such reactions are also known as combustion synthesis, reactive synthesis, self-propagating high-temperature synthesis. 

An authoritative review entitled The metal flux a preparative tool for the exploration of intermetallic compounds has been published by Kanatzidis etal. (2005). In this paper, containing a long list of references, several general and experimental aspects of this technique are discussed. The paper is enriched also by beautiful photographs of intermetallic single crystals, for instance a dodecahedral Ho-Mg-Zn quasicrystal grown from an Mg and Zn-rich flux. Special attention was dedicated to the use of molten metals as media (metallic fluxes) for the synthesis of different materials, and a number of key characteristics were underlined which the metal must possess in order to be a suitable flux. The following points were noticed ... 

Reilly and Wiswall (21) reported the synthesis of Mg2NiH4 by reacting the Mg2Ni intermetallic compound with hydrogen at 300 psi and 325°C, according to the following chemical equation ... 

B.P. Tarasov, V.N. Fokin, A.P. Moravsky, Yu.M. Shul ga, V.A. Yartys , and D.V. Schur, Promotion of Mlerene hydride synthesis by intermetallic compounds, I roc. of 12th World Hydrogen Energy Conference, Buenos Aires, Argentina 2, 1221-1230 (1998). 

Pavlyuk, V.V. 1993. Synthesis and crystal chemistry of the intermetallic compounds of lithium, Dr.Sc. Chemistry Thesis, Abstracts, L viv (L viv State University, L viv) pp. 1—46. 

However, the catalytic activity of contact mass is determined not only by copper concentration. Crucially important is also the structure of the crystal lattices of silicon, copper and the intermetallic compound Cn Si, which is formed during the alloying of silicon with copper or in the synthesis, since the structural failure seems to facilitate silicon or copper entering the reaction. The structure of the crystal lattice is largely determined by the way contact mass is prepared. 

It is supposed that the contact mass used in direct synthesis consists of two phases, free silicon and the intermetallic compound CusSi (r -phase). At the initial stage at synthesis temperature methylchloride interacts with the silicon atom from the intermetallic compound ... 

Tarasov B.P., Fokin V.N., Moravsky A.P., Shulga Yu.M., Yartys V.A., Schur D.V. Promotion of fullerene hydride synthesis by intermetallic compounds // Proceed. 12th World Hydrogen Energy Conf. Buenos Aires. Argentine. 1998. Vol. 2. P. 1221. 

In the work of CNF synthesis by decomposition of hydrocarbon gases over intermetallic compounds of La and Ni, made by us earlier, it was shown, that the particles of metal nickel can be formed directly during pyrolysis reaction [9]. 

For metals promoting other metals, an interesting case was studied by Hurst and Rideal.2 In the combustion of mixtures of hydrogen and carbon monoxide, using copper as the basic catalyst the ratio of the gases burnt depends on the temperature, and also on the amount of small additions of palladium made to the copper. The proportion of carbon monoxide burnt is increased by addition of palladium, a maximum proportion of carbon monoxide being burnt when 0-2 per cent, of palladium is. present. With further amounts of palladium, the ratio CO H2 burnt falls off slowly until, with 5 per cent, palladium, it is nearly the same as with pure copper. This effect of palladium is ascribed to the introduction of a new type of surface, the line of contact between palladium and copper, though the proof that this is the cause of promotion is perhaps not complete. Mit-tasch and others,3 in elaborate studies of the promotion of various metal catalysts, particularly molybdenum, for the synthesis or decomposition of ammonia, concluded that the formation of intermetallic compounds... 

Among intermetallic compounds not mentioned previously, Mg2Ni is a promising material for storing hydrogen. It has been shown that the combustion synthesis of this material is feasible, in spite of a relatively low heat of reaction. 

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