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 dif-ferent 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 car-bide(R-SiC)were investigated.The results show that:(1)after sintering at 2 200 ℃ 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 μm 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 μm,with the cold compressive strength,bulk density,and apparent porosity of 18.0 MPa,1.81 g·cm-3,and 40.8％,respectively.
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