Al_2O_3-SiO_2-TiO_2表面涂层对3D-C_f/SiC复合材料力学性能的影响

Effect of Al_2O_3-SiO_2-TiO_2 Coating on the Mechanical Properties of 3D-C_f/SiC Composites

采用溶胶凝胶法在三维碳纤维预制体(3D-Cf)表面形成Al2O3-SiO_2-TiO_2涂层,而后采用先驱体浸渍裂解工艺(PIP)制备了3D-Cf/Si C复合材料,通过SEM、XRD等分析测试手段以及三点弯曲等试验方法,研究了碳纤维的界面对复合材料的微观结构、力学性能的影响。结果表明,Al2O3-SiO_2-TiO_2涂覆处理后的碳纤维的强度约为原始碳纤维的96.8%,涂层碳纤维在复合材料断裂过程中起到了较好的增韧作用,涂层处理后的3D-Cf/Si C复合材料的抗弯强度达303 MPa,断裂韧度达6.5 MPa/m1/2。

A1203-Si02-Ti02 coating on three-dimensional braided carbon fiber(3D-Cf)were prepared by sol-gel method.Then the 3D-Cf/SiC composites with the interphase were all fabricated by the PIP process.And the influence of interfaces under different conditions on microstructure and mechanical properties of 3D-Cf/SiC composites were also investigated by means of XRD,SEM,as well as three point bending test.The results show that the Al203-Si02-Ti02 coated carbon fiber maintained 96.8%of its original strength.The mechanical properties of the composite with the coating reached a flexural strength of 303 MPa and a fracture toughness of 6.5 MPa/m12,which is attributed to the fact that the coated carbon fibers play a good toughening role in the fracture process of the composites.