Thermal Interface Material (TIM) is installed between a heat-producing device and a metal heat sink to help dissipate the component’s heat. However, the surfaces of various components have different waviness and roughness that causes gaps between them. These gaps fill with air, which has much higher thermal resistance than the TIM. In order to minimize this gap, a TIM should be conformable and flexible enough to fill the gaps.
There are a wide range of thermal interface materials on the market. They include pastes made of liquid polymers, pads based on wax, aluminum or graphite, solders and tapes. All of these can improve the thermal performance of an assembly but each has unique characteristics that need to be taken into account when selecting one for a specific application.
The best choice for a particular application may depend on the surface roughness of the mating components. Alternatively, the size of the gap between the components might be a factor. A TIM can also be selected to dampen vibration or to reduce component stress or warping in challenging environmental conditions.
A recent advancement in the category of TIMs is the use of pyrolytic graphite-based materials. These advanced thermal interface materials offer excellent stability, low abrasion and high performance. In addition, they are self-lubricating and can operate in a wide temperature range. They also have good mechanical properties, including tensile strength and breakdown voltage. They are also easy to assemble and can be used with a wide variety of adhesives.