Hot-pressed silicon carbide resistance to ITER-relevant thermal shock

Studies were carried out on the thermally induced erosion of silicon carbide as a result of pulsed infrared laser heating, simulating transient heat loads expected in the ITER tokamak divertor zone (laser pulse duration: \sim 0.5 ms). The critical parameters of pulsed heating that the material can withstand before the onset of erosion with loss of substance were determined. The experimentally observed damage threshold of hot-pressed silicon carbide under thermal shock of submillisecond duration corresponds to a temperature of about 1320 \pm 80 K, while a heat flux factor is about 23.9 \pm 1.6 \,\,\rm MJ \cdot \rm m ^-2 \cdot \rm s ^-0.5 (the sample was initially at room temperature). This result is relevant for surfaces with low roughness ( R_a \approx 1.1 \mu m, R_z \approx 5.3 \mu m). An increase in surface roughness leads to a decrease in the resistance of ceramics to pulsed heating. For rough surface ( R_a \approx 1.7 \mu m, R_z \approx 9.3 \mu m) critical temperature of about 790 \pm 50 K and heat flux factor of about 11.6 \pm 0.8 \,\,\rm MJ \cdot \rm m ^-2 \cdot \rm s^-0.5 were obtained. Thus, silicon carbide exhibits excellent resistance to transient heat loads as promising plasma-facing material, especially in the case of reduced surface roughness.