Thermal Resistance of Open-cell Metal Foam with Thermal Pad

This paper investigates the thermal resistance of sandwich structures consisting of open-type metal foams, base plate/surface and Thermal Interface Material (TIM) (thermal pad type). Two types of sandwiched study samples: Types 1 and 2, were investigated. The samples were prepared using metal foam structures, i.e., 20, 40, 60 PPI, and two commercial thermal pads, i.e., PC93, and PC94. The samples’ thermal resistance and thickness were measured under the compression loadings of 0 - 60 N using a thermal resistance tester that was developed in-house according to ASTM D5470 standard. The nanoindentation test indicated that PC93 had slightly higher hardness than PC94, with 0.0007 and 0.0004 GPa, reflecting their softness. The result shows that the samples’ thermal resistance is affected by compression force and decreases as compression load increases. The thermal resistance of the PC94 sample was reduced to 58% at 30 N load for 60 PPI, Type 1 configuration. The resistance decreases by 5% when the PPI increases from 20 to 60 PPI. This study demonstrates that joining metal foam, thermal pad, and base plate could reduce thermal resistance while increasing performance. It also provides insights into an alternative means of joining metal foams with other metals (or a base plate) in the development of heat exchangers.