Diffusion Parameters and Growth Mechanism of Phases in the Cu-Sn System

摘要

The tracer diffusion coefficients of the elements as well as the integrated interdiffusion coefficients are determined for the Cu₃Sn and Cu₆Sn₅ intermetallic compounds using incremental diffusion couples and Kirkendall marker shift measurements. The activation energies are determined for the former between 498 K and 623 K (225 °C and 350 °C) and for the latter between 423 K and 473 K (150 °C and 200 °C). Sn is found to be a slightly faster diffuser in Cu₆Sn₅, and Cu is found to be the faster diffuser in Cu₃Sn. The results from the incremental couples are used to predict the behavior of a Cu/Sn couple where simultaneous growth of both intermetallics occurs. The waviness at the Cu₃Sn/Cu₆Sn₅ interface and possible reasons for not finding Kirkendall markers in both intermetallics in the Cu/Sn couple are discussed.