Study of interaction between copper and melt of lead-free solders

Abstract

Problems of reactive diffusion at the interface solid phase - melt were studied theoretically and experimentally. A theoretical description of the kinetics of dissolution of the solid phase in the melt is presented for the case of planar dissolution. The main intention was to study experimentally the copper dissolution in melts of various solder alloys and the related reactive diffusion. We used pure Sn and Sn-Cu, Sn-Ag-Cu, Sn-Sb, Sn-Zn alloys as solder materials. Experiments aimed at the study of a Cu plate dissolving in the solder melt were carried out at various conditions. Concentration profiles of elements and thickness of layers of phases were determined by SEM and X-ray microanalyses (WDX, EDX) of specimens after their heating.

Keywords

• lead-free solders
• copper
• tin
• silver
• intermetallic compounds
• diffusion