LEAD-FREE SOLDERS FOR COPPER ALLOY WIRE MESH

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.