Mechanical and electromagnetic shielding properties of PIP-2D SiCf/SiC composite materials modified with Al filler

A two-dimensional continuous silicon carbide fiber reinforced silicon carbide composite material（2D SiCf/SiC composite material）was prepared by precursor impregnation cracking method（PIP method）using Al powder as the active filler. XRD, SEM and thermogravimetry were used to analyze the evolution behavior of the microstructure and composition of polycarbosilane pyrolysis products with various Al powder contents. The effects of various Al powder contents on the mechanical and electromagnetic shielding properties of the composites were studied by mechanical testing machine and vector network analyzer. The results show that as the mass fraction of Al filler increases from 0% to 40%, the bending strength of the composite material first increases and then decreases, and the maximum bending strength can reach 383 MPa. The introduction of aluminum filler leads to a gradual increase in the complex dielectric constant of the composite material, and the electromagnetic shielding efficiency gradually increases to 26 dB, which has been greatly improved. This is mainly due to the significant increase in the imaginary part of the complex dielectric constant caused by the increase in the content of Al filler, resulting in a significant improvement in the absorption and shielding efficiency of the composite material