Mechanism of SiC_f on Sintering Necks of Recrystallized Silicon Carbide Ceramics

Porous silicon carbide ceramics were prepared by using SiC powders and SiC_f as raw materials treated at 1600–2200 ℃ for 1 h in Ar atmosphere. The effects of SiC fiber on phase composition, microstructure, mechanical properties and pore size distribution of recrystallized silicon carbide were studied. It is demonstrated that the mass transfer rate of evaporation-condensation was increased at high temperatures owing to the decomposition of the silicon carbide fibers.Moreover, the growth of silicon carbide sintered necks and the mechanical properties of recrystallized silicon carbide cerami cs were effectively promoted. When the content of SiC fiber was 20 wt.%, the apparent porosity, bulk density and flexural strength at room temperature were (36.4 ± 0.1)%, (2.02 ± 0.01) g·cm^-3 and (76.40 ± 8.16) MPa, respectively.