Lead-Free Solders for Copper Alloy Wire Mesh

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 drop melt capillary purification in the experiment. The Sn–Ag–Cu solders wet the bronzes more actively than Sn–Pb (POS-61) and Sn–Bi alloys. The wetting of vacuum-annealed copper and bronze substrates by POS-61, O-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 representing a knitted soldered structure. The resistivity of O-2, SAC, Sn–Bi, and POS-61 alloys and the surface resistivity of the knitted soldered copper mesh are determined. The metallization of copper wire and soldering of mesh knots substantially influence the mesh surface resistivity.