Papers by Author: S. Messoloras

Abstract: In plasma facing components (PFC) for nuclear fusion reactors tungsten or carbon based tiles need to be cooled through a heat sink. The joint between the PFC and the heat sink can be realized using a brazing process through the employment of compliant layer of either a low yield material, like copper, or a high yield material, like molybdenum. Experimental verification of the induced stresses during the brazing process is of vital importance. Strains and residual stresses have been measured in Mo/CuCrZr brazed tiles using neutron diffraction. The strains and stresses were measured in Mo tile along the weld direction and at different distances from it. The experimental results are compared with Finite Element Simulations.

Abstract: The use of ceramic composite materials in aerospace applications requires the development of oxidization protection coatings which can withstand very high temperatures. HfO2 is a promising material as a high temperature oxidization protective layer. HfO2 coatings have been deposited by radiation frequency magnetron sputtering all over the surface of SiC substrates and were tested under re-entry conditions. Also their oxidization resistance in air in the temperature range 1100 to 1450°C has been examined. The coatings were found to be stable and well-adhering to the substrate even after 100 re-entry cycles. No oxidization of the underlying SiC structure is observed. Re-entry and oxidization tests result in the formation of HfSiO4 at the HfO2/SiC interface, which further promotes their oxidization resistance.