Nanostructured silicon carbide ceramics fabricated through liquid-phase sintering by spark plasma sintering

Fully dense nanostructured SiC ceramics were fabricated by spark plasma sintering of nanosized β-SiC powder with 40 nm in diameter through liquid-phase sintering at the total content of 10 vol % of sintering additives composed of 95 mol % AlN and 5 mol % Y2O3. The dense SiC ceramics sintered at 1900°C for 300 s consisted of equiaxed grains with the mean grain size of 70 nm without significant grain growth during the sintering. The full densification (>99% of theoretical) of the nanosized β-SiC powder was achieved at more than 5 vol % of the AlN–Y2O3 additive. The grain size decreased with increasing total amount of AlN–Y2O3 additive and decreasing holding time at 1900°C.