Effect of flake silver-plated copper particles on the property enhancement of electrically conductive adhesives.

To impart conductivity and improve the shear performance of epoxy resin-based adhesives, a simple, environmentally friendly, and stable method was used to deposit silver on the surface of 5 μm flake copper particles as a conductive filler. The core-shell metal fillers were prepared by utilizing the autocatalytic properties of Cu without adding any reducing agent during the reaction. An epoxy curing agent (MeTHPA) was used as a curing agent for the crosslinking reaction with epoxy resin to form a supporting skeleton of conductive components. The structure of flake plated Cu@Ag particles was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). It was verified that a layer of compact and crystalline silver with a concave-convex characteristic was deposited on the surface of copper particles. This feature has a positive effect on improving the performance of silver-plated copper particles. The results show that the optimal curing condition of flake plated Cu@Ag particle-epoxy composite electrically conductive adhesives (ECAs) was 200 °C for 1 h, the resistivity of flake plated Cu@Ag particle-epoxy composite ECAs with a content of flake plated Cu@Ag particles above 55 wt% was less than 6 × 10 Ω m, and the maximum shear strength was 8 MPa. The flake plated Cu@Ag particle-epoxy composite ECAs prepared by this method have excellent properties and have very important application value for advanced electronic devices.