| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite material suitable for an economical heat sink material with small coefficient of thermal expansion and comparatively high thermal conductivity. SOLUTION: Graphite powder and alloy powder containing such as Ti selected from among group 4A, group 5A, and group 6A elements, the main ingredient of which is Ag or Cu, are mixed and heated under a vacuum or an atmosphere of gas containing He, Ar or hydrogen at alloy fusing point or higher, and coating layer of metallic carbide such as TiC is formed on surface of the graphite grain, and a sintered compact is formed. The obtain composite material has relative density of 70% or more, thermal conductivity of 220 W/m.K or more at room temperature and mean coefficient of thermal expansion from room temperature to 200 deg.C is 5-15×10-6/ deg.C, and is suitable for heat sink for semiconductor. Carbide powder such as carbon fiber or SiC instead of graphite powder can be used. |
