Effect of Ni content on the diffusion-controlled growth of the product phases in the Cu(Ni)-Sn system

Baheti, Varun A and Islam, Sarfaraj and Kumar, Praveen and Ravi, Raju and Narayanan, Ramesh and Hongqun, Dong and Vuorinen, Vesa and Laurila, Tomi and Paul, Aloke (2016) Effect of Ni content on the diffusion-controlled growth of the product phases in the Cu(Ni)-Sn system. In: PHILOSOPHICAL MAGAZINE, 96 (1). pp. 15-30.

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Abstract

A strong influence of Ni content on the diffusion-controlled growth of the (Cu,Ni)(3)Sn and (Cu,Ni)(6)Sn-5 phases by coupling different Cu(Ni) alloys with Sn in the solid state is reported. The continuous increase in the thickness ratio of (Cu,Ni)(6)Sn-5 to (Cu,Ni)(3)Sn with the Ni content is explained by combined kinetic and thermodynamic arguments as follows: (i) The integrated interdiffusion coefficient does not change for the (Cu,Ni)(3)Sn phase up to 2.5 at.% Ni and decreases drastically for 5 at.% Ni. On the other hand, there is a continuous increase in the integrated interdiffusion coefficient for (Cu,Ni)(6)Sn-5 as a function of increasing Ni content. (ii) With the increase in Ni content, driving forces for the diffusion of components increase for both components in both phases but at different rates. However, the magnitude of these changes alone is not large enough to explain the high difference in the observed growth rate of the product phases because of Ni addition. (iv) Kirkendall marker experiments indicate that the Cu6Sn5 phase grows by diffusion of both Cu and Sn in the binary case. However, when Ni is added, the growth is by diffusion of Sn only. (v) Also, the observed grain refinement in the Cu6Sn5 phase with the addition of Ni suggests that the grain boundary diffusion of Sn may have an important role in the observed changes in the growth rate.

Item Type:	Journal Article
Publication:	PHILOSOPHICAL MAGAZINE
Publisher:	TAYLOR & FRANCIS LTD
Additional Information:	Copy right for this article belongs to the TAYLOR & FRANCIS LTD, 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND
Keywords:	Diffusion; intermetallics; defects; thermodynamics
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	18 Feb 2016 06:07
Last Modified:	18 Feb 2016 06:07
URI:	http://eprints.iisc.ac.in/id/eprint/53276

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