Bruno Hay, Oliver Beaumont, Nora Lambeng, Michel Cataldi, Christophe Lorrette, Kevin Knopp, Jürgen Hartmann, Fabia Beckstein, Dorothea Stobitzer, Nenad Milošević, Nenad Stepanic, Jiyu Wu, Petra Mildeova
- 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.
