Interfacial reactions between eutectic Sn–Pb solder and Co substrate

• Published in: Journal of materials science 2011-04, Vol.46 (8), p.2654-2661
• Main Authors: Wang, Chao-hong, Kuo, Chun-yi
• Format: Article
• Language: English
• Subjects: Activation energy; Alloys; Characterization and Evaluation of Materials; Chemical reaction, Rate of; Chemical reactions; Chemistry and Materials Science; Classical Mechanics; Constants; Crystallography and Scattering Methods; Eutectic reactions; Interface reactions; Lead; Materials Science; Organic chemistry; Polymer Sciences; Reaction kinetics; Reaction time; Solid Mechanics; Substrates; Thickness measurement
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-010-5121-0

This study examined the reaction couples of Co substrate with liquid and solid Sn-37 wt% Pb alloys, respectively. In the liquid/solid Sn–Pb/Co couples, one single-phase CoSn 3 layer was found at the interface at temperatures from 210 to 250 °C. The layer thickness was measured as a function of the reaction time. The layer growth rate increased with increasing temperature. The CoSn 3 layer growth was linear in the early stage and then became parabolic. In addition, the similar CoSn 3 growth behavior results were observed in the solid/solid Sn–Pb/Co couples from 150 to 170 °C. Nevertheless, one Pb-rich phase layer accumulated at the solder/CoSn 3 interface due to Sn consumption. Also, the reaction kinetics of Sn-37 wt% Pb/Co was symmetrically studied at various temperatures. The chemical reaction constants, diffusion constants, and the relevant activation energies were reported.