Thermal conductivity homogeneity and topography characterization

Thermal conductivity is a key parameter for evaluating materials involved in thermal management. Thermal conductivity is a consideration at all levels when thermal engineers design for optimum heat dissipation, bonding and homogeneity. Materials have emerged that are filled with high thermal conductivity materials such as boron nitride and graphite. The homogeneity of such materials has been measured through nondestructive localized thermal conductivity testing. The method involves an interfacial transient technique used to evaluate a material in a grid-wise fashion. The minimum sample area of each test location was 5 mm/spl times/50 mm, and the total time that was required for each test was under three minutes. A homogeneity factor (HF) is introduced to relate material results. One of the two formulations tested was determined to be slightly heterogeneous within statistical limits of the test procedure.