Abstract: “Disclosed is high thermal conductivity materials used as heat dissipaters in microelectronic and optoelectronic devices and power generators. Also disclosed is development of composite materials with high thermal performance and low production costs for use in semiconductor devices as heat dissipaters and a process for producing this material. The materials have a thermal conductivity above 200 Wm?1K?1 and a coefficient of thermal expansion in the range of 2 to 10×10?6K?1 (measured in the temperature range of 20 to 300° C. in at least two directions). The composite material is constituted in three phases: a phase consisting mainly of graphite flakes; a phase comprising particles or fibers of a flake separating material, selected from a ceramic material (such as SiC, BN, AlN, TiB2 and diamond) and carbon fibers, of high thermal performance in at least one direction; and a phase consisting of a metal alloy.