UV – visible pyrometry of refractory oxides at high temperature
V. Sarou-Kanian, J.-C. Rifflet and F. Millot
We report new experimental methods to determine temperatures of liquid and solid oxides in the range T = 2300–3500 K. The development of a UV pyrometer working at λ = 224 or 313 nm allows a comparison with more classical visible pyrometers. The principle consists of calibrating first a monochromatic UV or visible pyrometer aiming at a self-contained liquid pool of Y2O3 or Sc2O3 during its solidification respectively considered at T = 2712 K and T = 2740 K. This method has then been applied to the analysis of the free cooling curves of self contained liquid pools of 12 refractory simple di- and sesquioxides that have relatively well-known properties. Particular attention has been paid to the comparison between recommended and measured solidification apparent temperatures at 5 different wavelengths between λ = 224 and 800 nm. Comparable values are systematically obtained for apparent temperatures in the range [300–550 nm]. These values are in good agreement with recommended values for rare earth oxides.
Keywords: optical pyrometry, high temperature, melting point, refractory oxide, UV.