Theory for intermetallic phase growth between Cu and liquid Sn-Pb solder based on grain boundary diffusion control
Theory for intermetallic phase growth between Cu and liquid Sn-Pb solder based on grain boundary diffusion control
复制标题
DOI：
10.1007/s11664-998-0066-7
复制
发表时间：
1998-11-01
影响因子：
2.1
通讯作者：
Liang, J
中科院分区：
文献类型：
--
作者：
Schaefer, M;Fournelle, RA;Liang, J
在固-液扩散偶中，中间化合物层的形态影响相互扩散过程中的相形成动力学。在一些情况下，形成具有非常细的晶粒尺寸的中间化合物层。这种情况有利于晶界扩散作为主要的机制，通过层的运输。在发生晶粒粗化的系统中，粗化动力学将影响互扩散动力学。此外，对于某些固-液系统，观察到晶界开槽效应，这导致高度不均匀的层厚度;在液相渗透晶界的地方，层更薄。作为开槽效应的结果，穿过层的扩散路径沿沿着较短。这不同于标准的相互扩散模型，该模型假设扩散距离等于平均层厚度。提出了一种中间化合物层生长动力学模型，该模型适用于晶界扩散是主要输运机制的情况。该模型包含了晶界开槽引起的几何效应。该模型预测层生长遵循t（1/3）对时间t的依赖关系。铜与62 Sn-36 Pb-2Ag钎料之间的金属间化合物生长的实验数据表现出t（1/4）对时间t的依赖性。如果用本文提出的晶界扩散控制模型解释实验数据，则晶界扩散激活能为27 kJ/mole。
Kinetics of phase formation during interdiffusion in solid-liquid diffusion couples are influenced by the morphology of the intermediate compound layer. In some cases, an intermediate compound layer is formed which has very fine grain size. This condition favors grain boundary diffusion as the predominant mechanism for transport through the layer. In systems where grain coarsening occurs, the coarsening kinetics will influence the interdiffusion kinetics. In addition, for some solid-liquid systems, a grain boundary grooving effect is observed which leads to a highly nonuniform layer thickness; the layer is thinner where the liquid phase penetrates the grain boundaries. As a consequence of the grooving effects, the diffusion path through the layer is shorter along the grain boundaries. This differs from standard interdiffusion models which assume that the diffusion distance is equal to the average layer thickness. A model for growth kinetics of an intermediate compound layer is presented for the case where grain boundary diffusion is the predominant transport mechanism. The model includes the geometric effects caused by grain boundary grooving. The model predicts layer growth which follows a t(1/3) dependence on time t. Experimental data for intermetallic growth between copper and 62Sn-36Pb-2Ag solder exhibit a t(1/4) dependence on time t. If experimental data are interpreted in terms of the grain boundary diffusion control model presented in this paper, the activation energy for grain boundary diffusion is 27 kJ/mole.