Mechanical and electromagnetic shielding properties of SiCf/SiC composites fabricated by combined CVI and PIP process

Abstract 2.5D KD-I SiC f /SiC composites were fabricated by combined chemical vapor infiltration (CVI) and precursor infiltration-pyrolysis (PIP) processes for electromagnetic interference (EMI) shielding applications. The effects of PyC interphase and Al 2 O 3 filler on mechanical and EMI shielding properties of SiC f /SiC composites were studied. The PyC interphase effectively improves the accommodation of the fibers and matrix, and Al 2 O 3 filler compensates for matrix shrinkage and acts as a strengthening phase to improve the capability of bearing force for the composites. Thus, the composites with PyC interphase and Al 2 O 3 filler possess the maximum flexural strength and fracture toughness with the values of 313 MPa and 12.7 MPa m 1/2 . Owing to the existence of excess carbon and PyC interphase, the composites also maintain the highest SE T and SE A values of 30 and 20 dB, respectively, indicating its advantages as a kind of structural and functional materials. The superior SE A value is mainly attributed to the repeated reflection and dissipation of electromagnetic wave between the interfaces of PIP-SiC matrix and Al 2 O 3 particles.