Ag microflake-reinforced nano-Ag paste with high mechanical reliability for high-temperature applications

A silver (Ag) composite paste was fabricated based on Ag nanoparticles (NPs) and Ag microflakes (MFs). Robust interconnections were achieved after sintering in the temperature range of 150–225 °C. The shear strengths of the Ag MF + NP joints before and after thermal shock from − 50 to 150 °C for 1000 cycles were 155.7 ± 14.5 MPa and 78.4 ± 20.8 Mpa, respectively. The results show that the Ag composite paste not only has similar sintering properties to the Ag NP pastes but also exhibited superior mechanical reliability due to the addition of the Ag MFs. In addition, the sintered properties of different Ag pastes were discussed in terms of the coating organics, thermal behaviour and microstructure. The fracture modes after the shearing tests were analysed in detail. The Ag composite paste provides a potential solution for high-temperature applications.