Yes, but this is - in most cases - negligible. However, especially when determining the thermal diffusivity of thin and rapidly conductive samples, however, it is advisable to sprinkle the samples only lightly with graphite. In this way, the influence due to the graphite layer can be minimized. When determining the specific heat capacity by means of LFA, a covering graphite coating of the specimens and the references is indispensable. Ideally, for Ideally, the thermal diffusivity and specific heat capacity of such samples should be determined separately.