Understanding the performance characteristics of phase-change thermal interface materials

To aid in the understanding of phase-change thermal interface materials, the results of characterization testing performed on three currently available materials are discussed. These tests were performed using the methods of ASTM D 5470 modified to account for the properties of phase-change materials. These data reveal that while the materials tested show a variation in performance, they all achieve their minimum thermal impedance values by reducing their thickness and eliminating interfacial contact resistance after phase change. This paper also discusses an example of how to apply the test data to a specific application to predict the interface temperature difference when the interface mechanical specifications, mounting pressure and power density are defined.