Intermetallic Growth under High Hydrostatic Pressures

Yury S. Kaganovskii 

Bar-Ilan University, Ramat-Gan 52900, Israel

Abstract

L.N.Paritskaya1, Yu.S.Kaganovskii2, V.V.Bogdanov1, W.Lojkowski3
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1Department of Crystal Physics, Karazin Kharkov National University,
Kharkov 310077, Ukraine
2The Jack and Pearl Resnick Institute for Advanced Technology,
Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel
3High Pressure Research Center, Sokolowska 29/37, 01-142 Warsaw, Poland
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The kinetics and atomic mechanisms of intermetallic growth during bulk and surface interdiffusion in binary metallic systems have been considered. The problem attracts now much attention in view of effective technical applications of intermetallics as structural materials from monocrystalline till nanoscale ones with widen-spread net of interfaces. Two types of diffusion experiments are discussed: 1) bulk interdiffusion between the A and B metals that results to the growing AmBn intermetallic layers, and 2) surface diffusion from the A layer with a sharp boundary placed onto the substrate B, so that the intermetallic compound AmBn forms and spreads along the free surface
Intermetallic growth process consists in two competitive stages: interdiffusion of A and B atoms inside and/or along growing phase layer and chemical reaction at the interfaces. The relative contributions of these two processes determines the type of the intermetallic growth regime, which is characterized by different kinetic laws for the phase thickening and spreading along the free surface. The kinetic regularities of the intermetallic growth in the bulk and on the free surface at different conditions are analyzed theoretically and the methods for determination of the characteristics for interdiffusion and interfacial chemical reaction are proposed.
The developed methods are applied for treatment of experimental measurements of the phase growth kinetics, obtained on systems Cd-Ni, Cd-Cu, Cu-Zn in the temperature range 160-280C under high hydrostatic pressures up to 1 GPa. Application of high pressure allows us to evaluate such important characteristics as the activation volumes for diffusion in the bulk and along the surface as well as for chemical reaction at interfaces. On the base of these data and measured diffusion activation energies and pre-exponential factors the atomic mechanisms for chemical reactions as well as for bulk and surface diffusion in the growing intermetallics are suggested. Overview of known diffusion mechanisms in intermetallics, including non-stoichiometric ones, is presented and the essential differences between diffusion mechanisms in homogeneous and growing ordered phases is discussed.

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Presentation: oral at High Pressure School 2001 (4th), by Yury S. Kaganovskii
See On-line Journal of High Pressure School 2001 (4th)

Submitted: 2003-02-16 17:33
Revised:   2009-06-08 12:55
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