Electrical conductivity of silicon carbide composites and fibers

The electrical conductivity, σ, of silicon carbide (SiC) composites and fibers was measured for temperatures between 20 and 1000 °C in order to estimate the magnitude of magnetohydrodynamic effects for liquid metal blankets and a SiC composite structure. Two types of composites were tested: the first type had a matrix made by chemical vapor infiltration (CVI), the second type had a matrix made by polymer-impregnation-pyrolysis (PIP). The electrical conductivity of these materials differed by more than an order of magnitude, 650 (Ωm)−1 for CVI and 22 (Ωm)−1 for PIP composites at 1000 °C. This difference is attributed to the different carbon content of the materials. Several CVI composite samples were irradiated in HFR Petten to doses of 1, 2 and 5 dpa at 750 °C. The thermal conductivity, after 1 dpa, dropped below 30% of the unirradiated value, the drop in electrical conductivity was much smaller.