Reactive diffusion in Al/Pt films and the determination of the diffusion coefficients of Al in amorphous Al2Pt

P. Gas, C. Bergman, G. Clugnet, P. Barna, A. Kovacs, J. Labar

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3 Citations (Scopus)

Abstract

The increasing development of nano-structured materials with a high interface/volume ratio calls for a better understanding of interfacial reactivity at a nanometer scale. Mechanisms of phase selection and growth are still poorly understood, especially when metastable phases are also involved. In this paper we study the initial stages of reaction between Al and Pt under different experimental conditions, namely solid state reaction in Al/Pt multilayers (SSR) and high temperature sequential deposition (HTSD) of Pt on AL In both cases an Al2Pt amorphous phase (a-Al2Pt) is formed as the first reaction product. We analyze the growth of this phase and show that it is limited by diffusion. The role of diffusion is however very different during SSR and HTSD. In the first case (SSR) diffusion limits the growth rate while in the second case the growth rate is fixed to a constant value (by the Pt deposition rate) and diffusion only controls the thickness at which the growth of a-Al2Pt stops. Using these two values (growth rate in SSR and critical thickness in HTSD) and their variation with temperature we deduce the diffusion coefficient of Al in a- Al2Pt. The two approaches lead to similar values of the diffusion coefficient. This similarity shows that despite its indirect character (analysis of the growth) reactive diffusion in thin films can provide good estimations of diffusion coefficients in experimental conditions (metastable phase, nanometer range penetration distances) for which classical methods have very limited possibilities.

Original languageEnglish
Pages (from-to)807-814
Number of pages8
JournalDefect and Diffusion Forum
Issue number194-199 PART 1
Publication statusPublished - Jan 1 2001

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Keywords

  • Amorphous AlPt
  • Diffusion Coefficients
  • Multilayer
  • Phase Selection
  • Reactive Diffusion

ASJC Scopus subject areas

  • Radiation
  • Materials Science(all)
  • Condensed Matter Physics

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