Diffusion and Segregation in Bulk Nanomaterials and Thin Layers

Abstract:

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The data are presented for Ni selfdiffusion and Au heterodiffusion in nanocrystalline Ni. Volume diffusion coefficients are much greater than those for a coarse – grained polycrystals extrapolated from high temperatures. Interface diffusion parameters were calculated based on the assumption that B – kinetic regime is realized at temperature range more than 448 K, while C – kinetic regime is realised at temperatures less than 423 K. The consistency of obtained results with the proposed cluster diffusion model is discussed. Diffusion in Au – Cu thin films (from several tens to several hundreds nanometers) was studied with the use of the Rutherford Back Scattering, RBS, under the kinetic regime B (448 – 523 K). The RBS spectra were transformed in the concentration depth profiles for both volume and grain boundary (GB) diffusion. The triple products Pn = snδDn (sn is the enrichment coefficient, while δ is the nanograin boundary width) were calculated using Whipple model. As a result of this analysis the s – value for Cu – Au system was determined to be of the order of unity. The paper is focused on a difference between GB diffusion parameters in nano – and coarse grained materials.

Info:

Periodical:

Defect and Diffusion Forum (Volumes 258-260)

Edited by:

Andreas Öchsner and José Grácio

Pages:

475-482

DOI:

10.4028/www.scientific.net/DDF.258-260.475

Citation:

B. S. Bokstein and O.N. Petrova, "Diffusion and Segregation in Bulk Nanomaterials and Thin Layers", Defect and Diffusion Forum, Vols. 258-260, pp. 475-482, 2006

Online since:

October 2006

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$35.00

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