Superior Plasticity of Silver-Based Composites with Reinforcing Pyrochlore

Silver (Ag) has difficult forming strong bonding with oxides due to its deep d band beneath the Fermi level and completely filled 4d orbital. Thus, it is difficult to fabricate silver-based composites with superior plasticity and processability because of the easy debonding at their interface. Herein, La₂Sn₂O₇ pyrochlore was used as a reinforcing phase for a silver matrix. The enhanced interfacial bonding strength of Ag-La₂Sn₂O₇ was confirmed both theoretically and experimentally, indicating that Ag could form more localized ionic bonding with La₂Sn₂O₇ than with SnO₂. The superior plasticity was further confirmed for the Ag-La₂Sn₂O₇ composite, as the uniform elongation (UE) of the Ag-La₂Sn₂O₇ composite was ~19%, i.e., ~14% higher than and 2.8 times that of the conventional Ag-SnO₂ composite. The plasticity enhancement mechanism was also unraveled by calculating the interfacial mobility. This work verified the usefulness of pyrochlore to fabricate silver-based composites with superior plasticity and also provides a new strategy for the construction of advanced silver-based composites for application in the electrical contact field.