Methods for experimental determination of solid-solid interfacial thermal resistance with application to composite materials

Interfacial thermal resistance (ITR) exists between filler and matrix in any composite material and has a significant influence on its effective thermal conductivity. To predict the effective thermal conductivity of composite material, the conductivities of each component as well as the ITR must be known. Theoretical models, like the acoustic mismatch model (AMM), allow for accurate ITR determination only for an idealized case of perfect contact (no interfacial gaps and good bonding). The interfacial bonding in typical composites for thermal conduction, like diamond-reinforced metal matrix composites (MMCs) is usually highly imperfect and the ITR, in composites of the same type, depends highly on the individual manufacturing conditions. Therefore, a great need exists for reliable experimental ITR measurement techniques. In this paper, the main difficulties regarding experimental ITR measurements are discussed. A review of measurement techniques is presented, with the main focus put on the principle of each technique and its appropriateness for the purpose of composite materials. The strengths and weaknesses of each technique are discussed.