| Summary: | 碩士 === 國立臺北科技大學 === 化學工程研究所 === 98 === This study investigated the effect of the non-reactive alloying elements on the growth kinetics of the intermetallic compound (IMC) formed between liquid Sn-based solders and Ag substrate between the temperature of 260-290℃. Experimental results showed that Sb, Pb, and Bi, the non-reactive alloys elements, did not react with Ag substrate. Only one IMC, Ag3Sn, was formed at the interface of the interfacial reaction between liquid Sn and Ag substrate. Base on the diffusion controlled reaction mechanism, a parabolic kinetic equation in which both Sn concentration and alloying element effects were quantified, was derived and verified by comparing the kinetic data obtained by using four different solders with Sn concentrations and alloying elements. The apparent activation energies for pure Sn , Sn-Sb, Sn-Pb, and Sn-Bi solders reacting with Ag, are 54.8, 40.7, 28.8, 24.9 KJ mol-1, respectively. Since the diffusion of Sn atoms through IMC is the rate controlling step, the activation energies of the intrinsic diffusion coefficients for these four Sn-based solders are the same. The variation between the above-mentioned four apparent activation energies, comprised of activation energy of the equilibrium constants and that of the intrinsic diffusion coefficients, showed that the activation energies of the equilibrium constants for four solders are varying with different alloying elements. Other than the effect of Sn concentration on the growth rate of Ag3Sn, the non-reactive alloying element also exerted on the pre-exponential factor of the equilibrium constant which multiplied by the bulk concentration of Sn in solder gives the surface concentration of Sn in Ag3Sn.
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