Cryogenics typically refers to operation at temperatures below 123K, or -150°C and in many branches of science and medicine it is necessary to perform experiments and run equipment at cryogenic temperatures, down to as low as a few degrees Kelvin. At these temperatures specialist materials are needed in order to provide sealing and thermal conductance, since standard heat sink compounds and sealing formulations may crack or craze, which in turn reduces sealing efficiency and reduces thermal conductivity.
There are many types of grease currently available, such as PFPE based products that quote operating temperatures well below 0°C. However, nearly all these products have a quoted operating temperature range limit of -80°C. Typical heatsink compounds are only quoted as working down to -50°C. The one exception is hydrocarbon based grease (with proprietary additives) which can operate all the way down to -269°C, the temperature at which liquid helium boils.
This paper will discuss the demands of cryogenic applications and research, looking at the behavior of hydrocarbon based grease for thermal contact and sealing.