Uncertainty of thermal diffusivity measurements using the laser flash method

The paper deals with the uncertainty analysis for thermal diffusivity measurements using the laser flash method. A general metrological characterization of the high temperature thermal diffusivity measurement apparatus has been carried out. The metrological investigation follows the general rules for the evaluation and expression of uncertainty in measurement. This work presents a brief introduction to the flash method. It summarizes the main disturbing phenomena that may significantly influence the accuracy of the thermal diffusivity measurement. It gives a detailed description of the high temperature laser flash experimental apparatus installed at Austrian Research Centers. The paper also gives results of test measurements of the thermal diffusivity of a standard material, i.e., austenitic steel X10NiCrMoTiB1515 in the temperature range 20-900 degrees C. The results are compared with literature data and discussed. Sources of measurement errors are analyzed; components of uncertainty are categorized according to their evaluation method. The results are subjected to rigorous statistical evaluation to determine the uncertainty associated with thermal diffusivity measurements.