颗粒级配对重结晶SiC蜂窝陶瓷显微结构与力学性能的影响

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

以不同粒径(0.5、25、38和45μm)α-SiC粉末为原料,采用重结晶烧结工艺制备碳化硅蜂窝陶瓷,探究了颗粒级配对重结晶碳化硅(R-SiC)显微形貌、孔径分布及物理性能的影响。结果表明:1)经2200℃保温1 h烧成后,与仅添加25、0.5μm双粒径颗粒级配相比,随着38和45μm粒径α-SiC的逐步引入,R-SiC蜂窝陶瓷的烧结致密度无明显变化,但R-SiC粗颗粒间的平均烧结颈面积增大,中位孔径提高且孔径分布更为集中。2)当α-SiC原料的颗粒级配为25、0.5、38μm三种粒径时,R-SiC蜂窝陶瓷力学性能达到最优,其常温抗压强度、体积密度、显气孔率分别为18.0 MPa、1.81 g·cm^(-3)、40.8%。

SiC honeycomb ceramics were prepared by recrystallization sintering usingα-SiC powders of different particle sizes(0.5,25,38,and 45μm)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 2200℃for 1 h,compared with the honeycomb ceramics with only 25 and 0.5μm SiC,those with the gradual introduction of 38 and 45μm 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 38μm,with the cold compressive strength,bulk density,and apparent porosity of 18.0 MPa,1.81 g·cm^(-3),and 40.8%,respectively.