熔融渗硅处理对PIP工艺制备的SiC_f/SiC复合材料性能影响

Influence of Melting-infiltration Treatment on the Property of SiC_f/SiC Composites Fabricated by Using PIP Method

采用前驱体浸渍裂解工艺及浸渍裂解-熔融渗硅复合工艺制备了SiC_f/SiC复合材料。首先采用前驱体浸渍裂解工艺及两种不同界面层的纤维布制备复合材料,当界面层为BN/SiC双界面层时,制备的复合材料弯曲强度为373±71MPa,体积密度为2.351g/cm^3,显气孔率为15%;当界面层为热解碳界面层时,制备的复合材料弯曲强度为717±59MPa,体积密度为2.263g/cm^3,显气孔率为21%。经熔融渗硅后,上述两种复合材料的弯曲强度分别为291±42MPa与320±134MPa,体积密度分别为2.504g/cm^3与2.496g/cm^3,显气孔率分别降至7%与6%。实验结果表明,界面层对复合材料性能影响较为显著,采用复合工艺能够明显降低材料孔隙率,熔融渗硅后材料性能下降,下降幅度与界面层类型有关。

SiC_f/SiC composites were made by using precursor infiltration and pyrolysis(PIP)combined with melt infiltration method.Firstly,SiC_f/SiC composites were fabricated by using PIP method with different types of interphases.SiC_f/SiC composites,with BN/SiC dual-layer interphase,have the bending strength of 373±71 MPa,and the density and porosity are 2.351g/cm^3 and 15%,respectively.SiC_f/SiC composites,with Py C interphase,have the bending strength of 717±59 MPa,and the density and porosity are 2.263 g/cm^3 and 21%,respectively.After the melting infiltration process,the bending strengths of the materials are 291±42 MPa and 320±134 MPa,respectively.Also,the densities of the materials are 2.504 g/cm^3and 2.496 g/cm^3,respectively,while the porosities of the materials are decreased to 7%and 6%,respectively.Results showthat interphases playan important role in the strength of the material.The combined process can decrease the porosity of the composites but also decrease the mechanical strength of the material,and the extent is relevant to the type of the interphases.