WETTING KINETICS AND THE INTERFACIAL INTERACTION BEHAVIOR BETWEEN ELECTROLESS NI-CU-P AND MOLTEN SOLDER

Formation of intermetallic compounds and wetting kinetics between an electroless Ni-Cu-P deposit and molten solder were investigated. The microstructure and phase of the interface were investigated with the aid of scanning electron-microscopy (SEM) and X-ray diffractometry (XRD). Intermetallic compounds Ni3Sn4 and Ni3Sn2 were formed between Ni-Cu-P deposit and solder with Cu existing in the intermetallic layer. The contact angles of molten solder on a Ni-Cu-P deposit, measured with the sessile drop method, decrease with increasing temperature and time. The activation energy for wetting of molten solder on a Ni-Co-P deposit was estimated to be 193.7 kJ mol-1.