Lead-Free Solders for Wire Mesh Based on Copper Alloys

Abstract

The wetting of compact materials made of pure copper and copper bronzes (tin, beryllium, aluminum) by low-temperature tin-based solders is studied with the sessile drop method with capillary purification of drop melt during experiment. The Sn–Ag–Cu solders wet the bronzes more actively than Sn–Pb (PОS-61) and Sn–Bi alloys. The wetting of copper and bronze substrates previously annealed in vacuum by PОS-61, О-2, Sn–Bi, CASTIN, and SAC alloys show that copper and beryllium bronze are wetted by solder alloys better. The Sn–Ag–Cu solders and Sn–Bi alloys are used for metallization and soldering of copper mesh structures. Soldered copper wire 0.1 mm in diameter is obtained to produce mesh with cells representing a knitted soldered structure. Electrical resistance of О-2, SAC, Sn–Bi, and PОS-61 alloys as well as specific surface resistance of the knitted soldered copper mesh are determined. The metallization of copper wire and soldering of the mesh knots substantially influence the mesh specific surface resistance.