TY - JOUR A1 - Hay, Bruno A1 - Beaumont, Oliver A1 - Lambeng, Nora A1 - Cataldi, Michel A1 - Lorrette, Christophe A1 - Knopp, Kevin A1 - Hartmann, Jürgen A1 - Beckstein, Fabia A1 - Stobitzer, Dorothea A1 - Milošević, Nenad A1 - Stepanic, Nenad A1 - Wu, Jiyu A1 - Mildeova, Petra T1 - Inter‑laboratory Comparison on Thermal Diffusivity Measurements by the Laser Flash Method at Ultra‑high Temperature JF - International Journal of Thermophysics N2 - thermal diffusivity measurements by the laser flash method in the temperature range from 23 °C to 3000 °C. The main objective was to assess the variability and coherency of thermal diffusivity measurements performed at ultra-high temperatures at the European level. Three refractory materials (molybdenum, tungsten and isotropic graphite IG210) were selected for this inter-laboratory comparison, due to their high melting point. The disk-shaped specimens needed were machined from the same blocks of materials in order to reduce any potential scattering of results between participants due to inhomogeneity effects. The homogeneity of the sets of specimens was studied by the pilot laboratory (LNE) before launching the comparison process. Thermal diffusivity measurements were then carried out by the seven participants on the three materials during two successive thermal cycles up to the maximum temperatures that can be reached by the devices used. The analysis of results showed a good agreement between the participants for temperatures above 400 °C, with relative deviations within the uncertainties of measurement and lower than ± 4 % for molybdenum, ± 5 % for isotropic graphite and ± 9 % for tungsten. Y1 - 2023 UR - https://doi.org/10.1007/s10765-023-03159-5 VL - 2023 SP - 44 EP - 48 ER -