Effects of surface roughness, temperature and pressure on interface thermal resistance of thermal interface materials

Using thermal interface materials (TIMs) is generally considered an effective way to reduce thermal contact resistance. In this paper, effects of surface roughness, temperature and pressure on TIMs’ performance are investigated. A variety of TIMs including thermal pads, carbon-based materials, phase change materials (PCMs) and low-melting-point alloys (LMPAs) are experimentally studied, and their performance is compared with the case without using any TIM. Results indicate that, when pressure is below 0.3 MPa, the interface thermal resistance (ITR) decreases when the pressure increases, but such a trend is not obvious when pressure exceeds 0.3 MPa. The increase of surface roughness causes the ITR of thermal pads and carbon-based materials to increase, but does not affect the performance of PCMs and LMPAs. Interface thermal resistance of carbon-based materials decreases a little as temperature increases and that of thermal pads is not affected by temperature in test range. The ITR of PCMs and LMPAs sharply decreases when temperature exceeds phase change point. When surface roughness is 0.8 μm, thermal contact resistance of aluminum is 189 mm2·K·W−1 at 0.2 MPa and 153 mm2·K·W−1 at 0.4 MPa, but the ITR of thermal pads is 136–395 mm2·K·W−1 at 0.3 MPa and the ITR of one carbon-based material is 165 mm2·K·W−1 at 0.5 MPa.