Direct observations of silver nanoink sintering and eutectic remelt reaction with copper

Ag nanoink sintering kinetics and subsequent melting is studied using in situ synchrotron-based X-ray diffraction. Direct observations of Ag nanoink sintering on Cu demonstrate its potential for materials joining since the Ag nanoink sinters at low temperatures but melts at high-temperatures. Results show low expansion coefficient of sintered Ag, nonlinear expansion as Ag densifies and interdiffuses with Cu above 500 °C, remelting consistent with bulk Ag, and eutectic reaction with Cu. The results demonstrate the usefulness of Ag nanoink as a high-temperature bonding medium.