Formation of intermetallic compounds in reaction between Cu–Ni alloys and solid Sn – a new look at the prominent effect of Ni

Diffusion-controlled interaction of pure Cu with Sn at 488 K results in the formation of ε-Cu3Sn and η-Cu6Sn5 intermetallic compounds, and small additives of Ni in the Cu-substrate (up to 1 at. %), do not influence phase composition of the diffusion zone. It was found that in the η-phase, Sn diffuses somewhat faster than Cu (and Ni) does, and diffusion porosity is developed in the vicinity of the substrate/reaction product interface.