Influence of Interdiffusion in Sn Solution on Growth of Cu₃Sn and Cu₆Sn₅ Formed in Semi-infinite and Finite Cu-Sn Diffusion Couples

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• 作者：Toshitada Shimozaki ; Je-hyun Lee ; Chan-Gyu Lee
• 关键词：binary system ; computational studies ; interdiffusion ; intermetallic compound ; solid solution ; solubility limit
• 刊名：Journal of Phase Equilibria and Diffusion
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：38
• 期：1
• 页码：17-29
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Crystallography and Scattering Methods; Thermodynamics; Engineering Thermodynamics, Heat and Mass Transfer; Ceramics, Glass, Composites, Natural Materials; Metallic Materials;
• 出版者：Springer US
• ISSN：1863-7345
• 卷排序：38

文摘

Reactive diffusion in the Cu-Sn binary system has been studied by using pure Cu/electrically plated Sn with 0.1-0.2 mm thicknesses diffusion couples (EP-couples) at 473 K. The interdiffusion coefficients, \(\tilde{D}\), of the Cu₃Sn and Cu₆Sn₅ diffusion phase layers were determined at the center of these layers by supposing linear concentration (\(C_{\text{i}}\))-distance (X) curves in these layers and by neglecting the interdiffusion in the Sn terminal solution (IDS) as the previous researchers have neglected it. By using \(\tilde{D}\) thus determined, the phase boundary concentrations for the layers obtained in this work and these parameters for the Cu terminal solution chosen appropriately, \(C_{\text{i}}\)-X curves were determined numerically for various values of interdiffusion coefficient, \(\tilde{D}_{\text{in Sn}}\), and the solubility limit of Cu mole fractions, \(N_{\text{Cu}}^{\text{in Sn}}\), in the Sn terminal solution by our method reported previously taking the molar volume change effect into account. The \(C_{\text{i}}\)-X curves obtained experimentally could be reproduced numerically well by neglecting IDS. This result, on the other hand, suggests a large influence of IDS in the semi-infinite diffusion couples (S-couples) or the diffusion couples used by the previous researchers. The quantitative evaluation of the influence in S-couples revealed that it makes the widths of the diffusion layers thinner than those in the present EP-couples in which the influence on the widths is negligibly small. The evaluation of the influence in the diffusion couples used by the previous researchers indicates larger values of \(N_{\text{Cu}}^{\text{in Sn}}\) than those reported as the value of the equilibrium phase diagram.