CircuitWorks® Silicone-free Heat Sink Grease Chemtronics CircuitWorks® Silicone-free Heat Sink Grease facilitates heat transfer away from electrical/electronic components and into heat sinks. This silicone-free compound shows no creep or migration over a wide temperature range. Thickened with a proprietary thermally conductive zinc oxide ceramic, the Chemtronics CircuitWorks Silicone-free Heat Sink Grease creates an effective heat sink interface in electrical/electronic equipment. Exceeds MIL-C-47113 for thermal conductivity and stable from -15°C to 200°C.