INTERMETALLIC COMPOUND FORMATION IN Ni/Sn DIFFUSION COUPLE AT ATMOSPHERIC AND AT 10−8 ATMOSPHERE PRESSURE

Abstract

The microstructure resulting from diffusion reactions, at solid-state temperatures, in Ni/Sn couples has been studied by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The Ni3Sn4 phase was the only reaction product which formed in the couples at temperatures from 150[Formula: see text]C to 220[Formula: see text]C. The growth kinetics of Ni3Sn4 layer followed the parabolic law with an apparent activation energy of 104[Formula: see text]kJ[Formula: see text]mol[Formula: see text]. The effect of the atmosphere on the microstructure of the interfacial layer was investigated at 220[Formula: see text]C for a pressure of 10[Formula: see text][Formula: see text]atm. A decrease in the growth rate of the phase layer was observed.

Study of Reactive Diffusion in Cu/Zn Diffusion Couple

“…Usually, formation of one or several inter metallic compounds occurs at the interface between two substances of different chemical natures as a result of inter diffusion in the couple. This phenomenon is known as reactive diffusion and has been observed in numerous cases as Cu-Sn (1) , Fe/Sn (2) , Ti-Al (3) , Au-Sn (4) and Ni-Sn (5) . The inter metallic compounds often have properties that are different from the base metals and excessive inter metallic compounds in a couple are detrimental (6) since they alter the mechanical (7) and electrical properties of the joint (8) .…”