Experimental Study of Filler Insertion Effect on Mean Thermal Contact Conductance(<Special Issue>Micro Mechanical Engineering)

A series of experiments have been performed to investigate the filler insertion effect on the temperature drop at the wavy contact interface ΔT and the mean thermal contact conductance h_<m,f>. Representative behavior of ΔT against the mean nominal contact pressure p_m is clarified, and the effect of an interval of time on ΔT is shown for the silicone filler with thickness δ_<f0>=2mm. The silicone elastomer is proved effective to increase h_<m,f> despite its low thermal conductivity. Further, it is shown that h_<m,f> of 0.5mm thick silicone filler becomes two to three times higher than that of bare contact under the unloading process. However, it is also shown that h_<m,f> decreases with increasing δ_<f0>, therefore filler insertion with improper thickness results in a reverse effect on increase in h_<m,f>. As for metallic filler insertion using an aluminum or a copper foil, only a little improvement in h_<m,f> is obtained in spite of its high thermal conductivity.