| The electronics industry requires a thermal management material with high thermal conductivity and adjustable coefficient thermal of expansion. High thermal conductivity (1000W/mK) graphite is an exceptionally good medium for heat transfer in electronics, but limited as a heat spreader due to low fracture toughness and difficulty to metallize. Integration of graphite in to other metals such as copper and aluminum which have good thermal conductivity will create an engineered metal matrix composite. These MMC's will have all the desirable characteristics for use in electronic systems.; Since graphite does not like to wet with these metals surface modification graphite is necessary to promote wetting between graphite fibers and metals. The graphite fiber surface is modified with trace elements molybdenum, chromium and tungsten to improve wetting. Alternatively, these wetting agents are reaction bonded to the graphitic fibers to form adherent carbides to improve wetting.; These methods to surface modify graphite were successful to manufacture MMC's with thermal conductivity between 285.6 and 783 W/mK. An adjustable coefficient of thermal expansion (CTE) was achieved between 6.7 to 16.7x 10 -6/°C by varying the graphite content and orientation. These MMC's were characterized by SEM, TEM and XRD to determine surface morphology, porosity and interfacial reaction between carbon fibers and the liquid metal. The obtained thermal conductivities and CTE's are very high when compared to the practical thermal management materials in use now. |
