Growth kinetics of intermetallic compounds between Sn-9Zn solder and electroplated Fe-42Ni metallization

Interfacial reactions and growth kinetics of intermetallic compound layers formed between Sn-9Zn solder and electroplated Fe-42Ni metallization were investigated after ageing at 120,150 and 170 degrees C for up to 360 h. Experimental results show that the intermetallic compound formed at the interface was mainly delta-FeZn8.87 phase, rather than the FeSn2 phase. The reason is that the attraction between Zn and Fe is stronger than that of Sn and Fe. The growth exponent n for delta-FeZn8.87 phase was found to be about 0.5, indicating that it grew by a diffusion-controlled process. The activation energy for the growth of delta-FeZn8.87 phase was determined to be 42 kJ/mol, which is in good agreement with the reported data. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.