Power modulation technique for noncontact high-temperature calorimetry

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Abstract
A new noncontact calorimetric method has been developed based on inductive heating of a metallic spherical bulk sample by a power‐modulated radio‐frequency field under ultrahigh vacuum conditions. From the pyrometrically measured temperature response the specimen’s external (due to radiative heat loss) and internal relaxation time (due to thermal conductivity) are found to differ by more than two orders of magnitude allowing the specific heat as well as thermal conductivity of the sample to be determined as a function of temperature. The agreement between the measured and predicted temperature response for solid Nb demonstrates the applicability and accuracy of the method which is particularly useful for metastable or chemically reactive samples at high temperature.