Preparation and properties of Y₂O₃/Sn-58Bi composite solders

In the present work, the Y₂O₃/Sn-58Bi composite solders have been prepared by powder metallurgy method. The melting point of the solder was slightly affected by the addition of few amount of Y₂O₃. With the increase of the amount of Y₂O₃, the density and vickers microhardness were firstly increased to the peak value and then decreased with further addition of Y₂O₃, while the contact angle demonstrated the converse tendency. Compared with Sn-58Bi solder, the strength of the composite solder was slightly increased while the ductility was significantly improved after the addition of 0.1 wt.% Y₂O₃, solving the brittle problems of the traditional Sn-58Bi solder. Further observation of the fracture surface indicated that the addition of Y₂O₃ could refine the grain size of the Sn-58Bi and inhabits the propagation of cracks, which improve the ductility of the Sn-58Bi.