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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Thermal Contact Resistance of Gamma-Irradiated Metallic Foil and Carbon Nanotube Thermal Interface Materials

Get access (open in a dialog) DOI: 10.1615/IHTC15.tmg.008807
pages 8127-8137

Abstract

Thermal management is of fundamental importance in the design and simulation of electronic devices and components critical to system performance. Often, heat transfer across the interface of contacting materials can consume a significant fraction of the overall thermal budget. Thermal interface materials (TIMs) serve as a means of reducing thermal contact resistance (TCR) by increasing real contact area at the interface, thus enhancing the flow of heat from source to sink. In space systems, TIMs are exposed to high doses of gamma radiation due to the lack of an atmosphere to serve as an absorbing medium. With typical design lifetimes of 5 years or more, total radiation exposure can be significant and can affect the structure and performance of the TIM. Here, we report measurements of the pressure-dependent TCR of metallic foils and carbon nanotube TIMs (CNT-TIMs) in both vacuum and air ambient environments. The TIMs were irradiated in a gamma cell at a rate of 200 rad/s to a total dose of 50 Mrad. TCR was measured before and after gamma-ray irradiation using a one-dimensional steady-state calorimetric technique at room temperature and contact pressures ranging from 0.5 to 10 MPa. CNT-TIMs are shown to exhibit the lowest TCR of any of the tested interface materials, about 38% lower than a plain copper foil.