Study on microstructure and thermal properties of a CNF/Cu nanocomposite fabricated using chemical mixing

Highlights: • CNF/Cu composite having higher thermal conductivity (435 W/mK) than copper was developed using chemical mixing. • Microstructure and thermal properties of CNF/Cu nanocomposites were studied in depth. • Electroless copper plating on CNFs enabled them to become embedded inside copper particles. • The chemical mixing method successfully solved the non-uniform dispersion of CNFs in copper matrix. The microstructure and thermal properties of a carbon nanofiber reinforced copper matrix (CNF/Cu) nanocomposite processed by chemical mixing, with an electroless plated copper coating on the CNFs, were analyzed in depth and compared with those of nanocomposites processed by conventional mechanical powder mixing and wet powder mixing. The electroless copper plating on the surfaces of the individual CNFs enabled them to become embedded inside copper particles, which successfully solved the non-uniform dispersion of CNFs in Cu matrix, the most important problem in CNF/Cu nanocomposite manufacturing. The CNF/Cu nanocomposite prepared by chemical mixing had well dispersed CNFs, no pores, and no intermediate phase which can be a cause of thermal resistance. Its thermal conductivity was accordingly much higher (435 W/mK) than the nanocomposites processed by mechanical powder mixing and wet powder mixing, as well as the theoretical thermal conductivity of copper (398 W/mK).