Some Aspects on the Sintering of Cu-Sn Compact

Abstract

To clarify the sintering phenomena of Cu-Sn compact, characteristics of thermal dilation and electric resistance during sintering (in argon atmosphere up to 850°C) were studied. The results obtained were as follows.1) Thermal dilation curves show that they have a maximum point at about 550-600°C and have three marked points at about 200, 400 and 700-800°C where expansion or shrinkage stop for a while, and that the largest shrinkage occurs overs 800°C. It is concluded that these temperatures correspond to those of liquid phase formation and phase transformation which are respectively due to the melting of Sn at 232°C, 6 formation (η→ε+L) at 415°C, liquid phase formation(γ→γ+L) at 710°C, and β formation (γ/+L→β+L) at 755°C.2) Elctric resistance curves show that they have two marked peaks at about 200 and 700-800°C. It is considered that the peak at 200°C is owing to the increase of the contact point of grain caused by melting of Sn, and the other at 700-800°C is owing to that caused by liquid phase formation described above. Then, it is concluded that the structure of the Cu-Sn compact sintered over 800°C is completely mono-phase, α.