Stability of porous SiC based materials under relevant conditions of radiation and temperature

Porous SiC samples with different percentage of sintering additives have been manufactured by the so-called sacrificial template method at the Ceit-IK4 Technology Center (San Sebastián, Spain). Material stability under ionizing radiation and high temperature conditions considering electrical conductivity and microstructure has been evaluated at Ciemat (Madrid, Spain). Electrical conductivity was measured as a function of temperature before and after irradiation with 1.8 MeV electrons up to 23 MGy (∼10 −6 dpa), and radiation induced conductivity (RIC) was also examined during irradiation at 550 °C for different dose rates (from 0.5 to 5 kGy/s). Electrical conductivity increase with irradiation dose was observed to occur. Posterior XRD analysis allowed interpret radiation induced modification of the electrical conductivity in terms of changes in the SiC crystalline structure. Although neither RIC nor electrical degradation is seen to be an issue when data is extrapolated to future fusion devices radiation levels, the observed phase transformation at relatively low ionizing dose might affect structural stability of SiC-based materials.