Hard‐particle Reinforced Composite Solders Part 1: Microcharacterisation

A series of composite solders in 63/37 Sn/Pb was prepared: Cu₆ Sn₅ (10, 20,30 wt%); Cu₃ Sn (10, 20, 30 wt%); Cu (7.6 wt%); Ag (4 wt%); and Ni (4 wt%). These composite solders were prepared by two procedures: (A) admixture with solder paste; and (B) admixture with molten solder. The original particulates and the final composite solders were analysed and characterised by SEM (scanning electron microscopy) EDX (energy dispersive X‐ray), and ESCA (electron spectroscopy for chemicals analysis); or XPS (X‐ray photoelectron spectroscopy). A variety of morphological characterisations, intermetallics and porosities were noted. Good wetting was noted in all cases, and porosity was greater for method (A). The particulates all exhibited excellent binding to the solder matrix.