Low Temperature Thermal Conductivity of Several Greases

Abstract

The temperature dependence of the thermal conductivity of silicone vacuum grease, Cry-Con grease (a copper loaded electrically insulating grease), and Eccotherm TC-4 (a specially formulated paste based on silicones and fillers) has been measured at liquid helium temperatures. It is concluded that the (thermal) greases examined have thermal conductivities in bulk corresponding approximately to those of thermal insulators. The successful use of thermal bonding greases to effect heat transfer at liquid helium temperatures and below requires very thin layers of the greases, in order to avoid the deleterious effect of their poor thermal conductivity in bulk.