Abstract: The invention concerns a thermal transfer layer with high transfer coefficient between two materials which can have different expansion coefficients. The thermal transfer layer comprises expanded graphite inserted between the materials which are selected from among carbonaceous materials, ceramics and metals or metal alloys. The expanded graphite is either inserted in the form of a rolled or compressed sheet, or is compressed in situ. The invention also concerns a device for the cooling of a structure subjected to intense, continuous, intermittent or pulsating heat flux, by means of fluid circulation tubes placed in the passages in the structure. A flexible material which is a good heat conductor in a compressed state, such as expanded graphite, is placed between the structure to be cooled and each tube.