Pb-Sn system was widely used in electronic industry because of their unique properties. However, being a heavy metal, it is toxic for human health . Due to the environmental and health concern, WEEE and RoHS, have forbidden the using of lead in the electronic industry [2, 3]. Among many Pb-free solder, the Sn-Ag-Cu solder are the most promising candidate for its wettability and better mechanical properties and thermal resistance [4, 5]. The formation of intermetallic and its growth kinetics depends on the composition of the solders and how each of the solder components interacts with the substrate . In order to improve the properties and microstructure of the solder, the addition of alloying elements such as Ni, Zn, Co, Sb, Al, Fe and Bi have been investigated [7-12].
The Sn-Ag-Cu solder system with the addition of Ni has become popular because of their superior soldering properties and low cost . Nickel is commonly used to provide a diffusion barrier between Cu substrate and Sn-based solder alloy in order to suppress the formation Cu3Sn [7, 9]. Ni lowest reaction rate with an effective additive since it forms a stable phase in the Ni-Sn binary system [7, 14]. According to Tay et al, when Ni was added into solder, the growth rate of Cu3Sn was decreased from 29.8 × 10-19 m2s-1 into 2.50 × 10-19 m2s-1 .
The homogeneous distribution of alloying elements may play a part in solder properties. Therefore, the selection of processing techniques is important in order to get a homogeneous distribution of solder element. Powder metallurgy route is an alternative method to prepare solder material. It offers many advantages such as refine microstructure, near net shaping and greater materials utilization [16, 17, 25]. In this study, solder material was prepared using powder metallurgy techniques and particular emphasis was placed to correlate the effect of Ni addition to Sn-3.5Ag-1.0Cu on the growth kinetics of Cu6Sn5 and Cu3Sn intermetallics.
2. Experimental Procedure
The materials used in this study were 99.8% trace metal basis of Sn powder, 99.9%...