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: ∼ 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±80 K, while a heat flux factor is about 23.9±1.6 MJ·m -2 ·s -0.5 (the sample was initially at room temperature). This result is relevant for surfaces with low roughness (R a ≈ 1.1 μm, R z ≈ 5.3 μm). An increase in surface roughness leads to a decrease in the resistance of ceramics to pulsed heating. For rough surface (R a ≈ 1.7 μm, R z ≈ 9.3 μm) critical temperature of about 790±50 K and heat flux factor of about 11.6±0.8 MJ·m -2 ·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.