Performance evaluation of carbon nanoparticle-based thermal interface materials

Abstract

The thermal performance of various carbon nanoparticle-based thermal interface materials was evaluated using a variety of criteria such as thermal contact conductance, thermal conductivity, and bond line thickness. The thermally conductive filler materials used in this study were carbon black, graphene nanoplatelets, and a hybrid filler consisting of graphene and carbon black, respectively. The effectiveness of these filler materials was compared. The results indicated that the effectiveness of filler materials depends critically upon surface roughness, bond line thickness, and contact pressure. For smooth mating surfaces, the hybrid filler is more effective than carbon black, which is, in turn, more effective than graphene nanoplatelets. For rough mating surfaces, graphene nanoplatelets are slightly more effective than the hybrid filler, which is, in turn, more effective than carbon black. Graphene nanoplatelet-based materials have high thermal conductivity, but provide poor gap filling capability due to limited compliance. Carbon black-based materials provide good gap filling capability on thin bond lines, but have low thermal conductivity and require high filler loading to be effective. The hybrid filler is the optimum choice for maximizing benefit, because it has the major advantages of the other two types of fillers, without suffering from their disadvantages. All of these materials suffer reduced thermal performance with thicker bond lines at high filler loading, and there exists an optimum filler content at which a maximum thermal performance is achieved. Excessive filler loading adversely affects the performance of the derived thermal interface material.