THERMAL CONTACT RESISTANCE MEASUREMENTS

We started with a conventional steadystate direct method to measure thermal contact resistances (TCR) of Cu/Cu, SS304/SS304 and Al2O3 /Al2O3, but later found that it is not applied to measure the TCR of thin test pieces. In the study of thermal resistance of the interface materials with graphite sheets and gel sheets with the direct method, we found that graphite sheet can decrease TCR at high contact pressure but not at low contact pressure while a gel sheet has a constant thermal resistance in both vacuum and atmospheric pressure This led us to develop an indirect method which can measure TCR without inserting temperature sensors into the test pieces. The indirect method was successfully applied to measure the TCR of Cu/Cu. In order to completely remove the additional TCRs introduced in the indirect method, we developed a new method by attaching additional temperature sensors directly onto the backsides of the test pieces. The TCR of Si/Al2O3 was measured with the new method. Both the indirect method and the new method can be used to measure the TCR of thin test pieces.