Screen Printed Graphite Nanoplatelet and Nanoparticle Composites for Thermal Interface Materials Application

Abstract

Screen printed thermal grease of embedded nanoparticles (NPs) on top of graphite nanoplatelets (GNPs) composites are fabricated with pre-defined mesh patterns as a new generation of Thermal interface materials (TIM). In the present study, the NPs thermal grease can be uniformly deposited and reliably controlled thickness in 45 μm in the matrix GNPs. Furthermore, three types of TIM are tested based on the hybridization of GNPs and the nanoparticles (NPs) thermal grease. The hybrid materials are fabricated via screen printing process to ensure the conformal uniformity of NPs thermal grease spreading on the GNPs. The performance of fabricated materials such as temperature, applied pressure, heat flux, and TIM thickness are concurrently tested in the heat flux values in the range of 0---5.3 W cmź2 and the pressure range 0---5.6 kgf/cm2 using a standard TIM tester. The steady-state heat flow technique of ASTM D5470-06 are fully adopted. The measured thermal conductivity of GNPs (3 layers) +NPs (2 layers) composite of a thickness of 195 μm is 0.2 W/m K, compared favorably with the sample of only one layer GNPs (0.11 W/m K). Experimentally, the measured trend in the change of specific thermal conductivity with pressure was in good agreement with the data presented in the literature. In the actual implementation of insulated gate bipolar transistors (IGBT) for 15 kW inverter system used for the renewable energy (solar and wind power), the fabricated composite with GNPs (3 layers) and NPs (2 layers) can effectively reduce the peak temperature of IGBT chip and is very promising in preventing thermally-related failure for the IGBT.