Effect of P and rare-earth La on microstructure and property of AgCuZnSn brazing alloy

The P and rare-earth La were added into AgCuZn-Sn brazing alloy.The effect of P and La on the microstructure and property of AgCuZnSn cadmium-free brazing alloy sy stem was investigated. The results showed that the addition of P could decrease the interfacial tension between liquid brazing alloy and specimen, and the wettability and fluidity were also improved.With the addition of La, the wettability of the brazing alloy was improved.while the wettabilty decreased as the content of La increased.The microstructure of AgCuZnSn brazing alloy consisted of CuZn intermetallic compound, Cu_5.6Sn intermetallic compound and Ag-rich phase.The black Cu₃P compound was generated when P was added.And addition of La could make microstructure homogeneous, and restrain the growth of intermetallic compound.