Effects of particle gradation on microstructure and mechanical properties of recrystallized SiC honeycomb ceramics.

SiC honeycomb ceramics were prepared by recrystallization sintering using α-SiC powders of different particle sizes (0.5, 25, 38, and 45 µm) as raw materials. The effects of the particle gradation on the micro-morphology, pore size distribution, and leading physical properties of the recrystallized silicon carbide (R-SiC) were investigated. The results show that: (1)after sintering at 2 200 °C for 1 h, compared with the honeycomb ceramics with only 25 and 0.5 µm SiC, those with the gradual introduction of 38 and 45 |jm SiC have similar sintered density, larger average sintered neck area between R-SiC coarse particles, higher median aperture size, more concentrated pore size distribution, and fist increased and then declined cold compressive strength; (2) the mechanical properties of R-SiC honeycomb ceramics are the optimal when the particle gradation is 25, 0.5, and 38 |jm, with the cold compressive strength, bulk density, and apparent porosity of 18.0 MPa, 1.81 g · cm^-3, and 40.8% respectively. [ABSTRACT FROM AUTHOR]