Thermal grease(also called CPU grease, heat paste, heat sink compound, heat sink paste, thermal compound, thermal gel, thermal interface material, or thermal paste) is a thermally conductive (but usually electrically insulating) compound, which is commonly used as an interface between heat sinks and heat sources such as high-power semiconductor devices. The main role of thermal grease is to eliminate air gaps or spaces (which act as thermal insulation) from the interface area in order to maximize heat transfer and dissipation. Thermal grease is an example of a thermal interface material. As opposed to thermal adhesive, thermal grease does not add mechanical strength to the bond between heat source and heat sink. It will have to be coupled with a mechanical fixation mechanism such as screws, applying pressure between the two, spreading the thermal grease onto the heat source.

<application / Characteristics> Thermal grease: Mostly used in the electronics industry, it provides a very thin bond line and therefore a very small thermal resistance. It has no mechanical strength (other than the surface tension of the grease and the resulting adhesive effect) and will need an external mechanical fixation mechanism. Because it does not cure, it is used only where the material can be contained or in thin application where the viscosity of the grease will allow it to stay in position during use.