Solid state interfacial reactions in electrodeposited Ni/Sn couples

Ni/Sn couples, prepared by sequentially electroplating Ni layers and Sn layers on metallized Si wafers, were employed to study the microstructures and growth kinetics of Ni-Sn intermediate phases, when the Ni/Sn couples were aged at room temperature or annealed at temperatures from 150 to 225℃ for various times. The results show that the NiSn phase and Ni₃Sn₄ phase are formed, respectively, in the aged couples and annealed couples. The Ni₃Sn₄ layer is continuously distributed between the Ni and Sn sides in the annealed Ni/Sn couples. The Ni₃Sn₄ growth follows parabolic growth kinetics with an apparent activation energy of 39.0 kJ/mol.