Manufacturing and characterization of porous SiC for flow channel inserts in dual-coolant blanket designs

SiC is the primary candidate for the flow channel inserts in dual-coolant blanket concepts. Porous SiC ceramics are attractive candidates for this non-structural application, since they can satisfy the required properties through a low cost manufacturing route, compared to SiCf/SiC. This work shows first results of the manufacturing of porous SiC ceramics prepared with different amounts of Y2O3 and Al2O3 as sintering additives. C powders were used as pore-formers by their burnout during oxidation after sintering. Comparison of microstructure, porosity, flexural strength, thermal and electrical conductivity and corrosion under Pb–15.7Li of porous SiC without and with sintering additives is presented. The addition of 2.5 wt.% of Y2O3 and Al2O3 improves the mechanical properties, and reduces the thermal and electrical conductivity down to reasonable values. Preliminary corrosion tests under Pb–15.7 Li at 500 °C show that the absence of a dense coating on porous SiC leads to poor corrosion behavior.