Management of thermal interfacial resistance for a reparable thermal interface

Thermal interfacial resistance is characterized with state-of-the-art thermal interface materials (TIMs), including a grease, a phase change material (PCM) and a graphite-enhanced sheet (GES). A test bench has been developed to control the holding pressure with a built-in heating and cooling system. Pressures and temperatures are measured at multiple locations along the interface to be able to examine the effects of imbalance on the thermal resistance. Results indicate that the GES has a low thermal resistance of about 26 K-mm²/W at 330 kPa while the phase change material has a value of 34 K-mm²/W at a comparable pressure. The grease has a low value of 20 K-mm²/W, but the interface would not be reparable. The PCM and the GES have a metal foil on one of the surfaces, allowing them to construct a reparable interface. The effect of imbalance in holding pressure has also been examined. An imbalance in temperature grows with pressure, and a mechanical inclination of binding surfaces relative to each other is suggested as a cause of the temperature variation.