MEN Weiwei 1,2, MA Na 1,2, ZHANG Shuwei 1, XUAN Lixin 1,2
(1. Research Institute for Special Structures of Aeronautical Composites AVIC, Ji'nan 250023, Shandong, China;
2. The Aeronautical Science Key Lab for High Performance Electromagnetic Windows, Ji'nan 250023, Shandong, China)
Abstract: In order to prevent the interface reaction between fiber and matrix, the interface design of Si3N4/SiBN composites was carried out. First, the infiltration agent on the surface of Si3N4 fiber was removed by 500 °C heat treatment. Then BN coated Si3N4 fiber was prepared by precursor impregnation and pyrolysis technology. After 4 rounds of impregnation, curing and pyrolysis, dense Si3N4/SiBN composites were prepared. Study shows: 500 °C heat treatment can remove the infiltration agent on the surface of Si3N4 fiber; BN coating can effectively alleviate the strong bonding between Si3N4 fiber and SiBN substrate. The density of Si3N4/SiBN composite is 1.83 g/cm3, the flexural strength reaches 96.8 MPa, the dielectric constant and the loss tangent are 3.25 and 0.012.
Key words: wave-transparent material; precursor impregnation and pyrolysis; Si3N4/SiBN