Heat flow method can be adopted to measure the thermal contact resistance of two mating samples or thin film materials.
As shown in Figure 3a (cited from https://arxiv.org/pdf/1605.08469.pdf), testing samples are pressed together with controllable contact pressures. Figure 3a schematically show the measurement setup with 4-6 thermocouples placed inside the two mating samples at uniform intervals to measure local temperature gradience. The temperatures at both interface can be deduced from the temperature gradience (Figure 3b). Then thermal contact resistance can be calculated by the temperature difference divided by heat flow power.
Similarly, the thermal conductivity and thermal resistance of a thermal interface material (TIM) can be measured with a setup of metal block/TIM/metal block, as shown in Figure 3C. The two metal block (usually copper) has known thermal conductivity. TIM are usually employed to reduce thermal contact resistance. Commonly used TIMs include pressurized gases (e.g. helium, hydrogen), thermal greases (e.g. silicone oil, glycerin), thermal adhesive, thermal conductive pad and polymer matrix composited with high thermal conductive particulates such as silver and ceramics as fillers, phase change material, and solders
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