Join Mechanism of Press-Soldered Joints in Copper to Copper

Abstract

Copper to copper lap joint was made by the resistance heating, applying pressure simultaneously. The copper plate was pre-soldered and the alloyed layer was pre-formed by using Pb-50Sn solder and then joint mechanism of press-soldered joints was analyzed.
The reason of enhancing strength and heat resistance heated by applying voltage in press-soldered joints is summarized as follows.
(1) Solder composition turns to Cu-Sn alloy composition.
(2) Joint layer with higher melting point was formed in which Cu increases and Sn decreases.
(3) In terms of the crystal structure, Cu₃Sn, Cu₆Sn₅ and Cu(α) phases turns to Cu₄₁Tn₁₁ and Cu(α) phases which have high heat resistance.