Synthesis and characterization of Cu–GnPs coatings as thermal interface materials

Copper-graphene composites have great potential for thermal management applications in electronics due to the tailorable coefficient of thermal expansion (CTE) and thermal conductivity to match adjacent components. However, homogenous dispersion of graphene in the copper matrix is the key challenge to maximize its potentials. In this work, graphene nano-platelets (GnPs) were successfully incorporated into copper coatings using pulse reversed sediment electroplating. The synthetic Cu–GnPs composite coatings’ microstructure and GnPs dispersion in both plan-view and cross-section were characterized using the scanning and transmission electron microscopy as well as Raman spectroscopy. The CTE results of the Cu-GnPs in both the vertical and horizonal directions were measured to be about 17.8 and 17.3 ppm/K, respectively, as compared with 16.5 ppm/K from pure Cu coating. The electrical resistivity of the coating was 5.5 × 10−5 Ω·cm, retaining the same order as pure Cu.