Synthesis of Bi–Pb–Sn–Cd solder particles for joining Ag-plated PZT ceramics at 100 °C

The rapid development of current multifunctional and flexible electronics has posed increased demand for low-temperature solder materials. The joining of Ag-plated PZT ceramics at a low soldering temperature of 100 °C using Bi–Pb–Sn–Cd solder paste was demonstrated. The Bi–Pb–Sn–Cd solder particles with good solderability were synthesized by shearing liquid into complex particles (SLICE) method. The joining of Ag-plated PZT ceramic has been achieved by the formation of an intermetallic compound (IMC) layer consisting of Ag–Cd compounds at a relatively low soldering temperature of 100 °C. For the joints soldered at 100 °C for 8 h, the shear strength is 31 MPa. The re-melting point of the joint increases from 72 to 93 °C. The low soldering temperature of Bi–Pb–Sn–Cd solder pastes allows us to join PZT ceramics on flexible PET substrate at a quite low reflowing temperature of 100 °C. The samples are bendable and the Bi–Pb–Sn–Cd solder are thus usable for flexible applications .