Diamond-infiltrated carbon-carbon composites

Carbon composites of high thermal conductivity and low mass are attractive for heat sink materials in thermal management of electronics, particularly in aerospace applications. Barriers to their use arise from properties of carbon-carbon composites, such as high electrical conductivity, poor match of coefficient of thermal expansion (CTE) and highly anisotropic thermal conductivity, the last of which results in poor thermal conductivity normal to the plane of two-dimensional reinforcement designs. Use of electrically insulating coatings and compliant layers for CTE mismatch introduce barriers to efficient thermal energy transport out of the electronics package. Chemical-vapor-deposited diamond, with the attractive properties of its CTE, high isotropic thermal conductivity and high electrical resistivity, may be used to overcome these problems. Based on these principles, an innovative integral dielectric heat sink material has been developed which is comprised of a carbon-carbon composite partially infiltrated with polycrystalline diamond.