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以纳米SiO2为填料,采用先驱体浸渍裂解法制备2.5D-SiCf/SiC(D为维数,SiCf为SiC纤维)复合材料,研究了前驱液中纳米SiO2含量对复合材料力学性能的影响。结果表明,纳米SiO2的添加能有效抑制先驱体裂解过程中的体积收缩,提高致密度,但过量引入易导致浸渍液黏度过高,浸渍效率降低。纳米SiO2含量对材料力学性能有较大影响,添加纳米SiO2后材料的抗弯强度和断裂韧性均高于没有添加的样品,材料抗弯强度随纳米SiO2含量的增加先增大后降低。当浸渍液中纳米SiO2含量为6%时,复合材料具有优异的力学性能,抗弯强度达到211.1MPa。
Using nano-SiO2 as filler, a 2.5D-SiCf / SiC (D is the dimension, SiCf is SiC fiber) composite was prepared by precursor impregnation and pyrolysis. The effect of nano-SiO2 content in precursor solution on the mechanical properties of the composites was studied. The results show that the addition of nano-SiO2 can effectively inhibit the volume shrinkage during the pyrolysis of the precursor and increase the density. However, excessive introduction of the nano-SiO2 can easily lead to excessive viscosity of the impregnation liquid and decrease the impregnation efficiency. The nano-SiO2 content has a significant effect on the mechanical properties of the material. The flexural strength and fracture toughness of the nano-SiO2 are higher than those without the nano-SiO2. The flexural strength of the nano-SiO2 first increases and then decreases with the increase of nano-SiO2 content. When the nano-SiO2 content in impregnating solution is 6%, the composites have excellent mechanical properties and the flexural strength reaches 211.1MPa.