Thermal grease, also called thermal paste, is a spreadable compound specially designed for high thermal conductivity to reduce thermal interface resistance between two surfaces. Thermal Greases can be silicone based or silicone-free based compounds with thermally conductive filler particles that increase the overall conductivity of the mixture.
Thermal grease is a popular thermal interface material choice for many high performance thermal management applications. When two flat surfaces are mated together with grease, the grease spreads out and thins, decreasing the thermal resistance between surfaces. Higher forces, typically with the use of mounting hardware and spring forces, ensure the highest performance with thermal greases. When heated, grease can thin out further, which is why spring forces are typically required for most applications that will experience significant thermal cycling.
For higher volume applications that require consistent grease application, thermal grease can be screened on using a template that controls distribution and thickness of the applied grease. Products with pre-applied thermal grease are shipped with a protective grease shield to ensure the grease doesn’t capture any air pockets during installation and that the pattern is unchanged from application to installation. Thermal greases are also available in syringe and tub packaging, which is useful for low volume production, use in the test lab, or for prototyping. As the reuse of applied paste can introduce air pockets that can hinder thermal transfer, having extra thermal grease is ideal for retrofits, rework, and grease reapplication.