Silver nanoparticles decorated α-alumina as a hybrid filler to fabricate epoxy-based thermal conductive hybrid composite for electronics packaging application

Abstract

Silver-alumina hybrid fillers (Ag/α-Al2O3) were synthesized by a simple ‘heat and mix’ technique to increase the thermal conductivity of epoxy resin. The nano and micro coalition of Ag/α-Al2O3 could facilitate the effective 3 D phonon transfer system throughout the insulative epoxy resin and consequently reduced the interfacial Kapitza resistance. The Ag/α-Al2O3hybrid filled epoxy composite with 55 wt % (Ag/αA-55Ep) expressed the 9.8 fold thermal conductivity improvement than pristine epoxy. The filler content was optimized to maximize the interfacial and cohesive bond strength of composites through lap shear tests. The Ag/αA-55Ep hybrid composite demonstrated glass transition temperature (Tg) of 118 °C evaluated through dynamic mechanical analysis (DMA). At 5% weight loss, the thermal stability of the Ag/αA-55Ep composite was 324 °C as measured using thermo-gravimetric analysis (TGA). The logarithm of electrical conductivity of Ag/αA-55Ep composite was 0.023 (Ω cm)−1 which signified the semiconducting material range. Surface morphology and conductive networks were determined from the fracture surface analysis of the composites. Agari’s empirical model was adopted to analyze the obtained experimental thermal conductivity results. The Horowitz and Metzger method was also considered for activation energy analysis of optimized composite.