A Novel Oxide Ceramic Matrix Composite with High-Temperature Emw Absorption and Excellent Mechanical Performance

Oxide ceramic matrix composites (OCMC) are extensively used as thermal structural materials due to the heat-resistance, good mechanical properties and oxidation resistance, but they are rarely regarded as electromagnetic wave absorbing materials due to the high resistivity of oxide ceramics/fibers. A novel OCMC was designed and prepared by introduce the uniform BN interface and dense Si-based matrix into Nextel 610 (N610) fiber preform at low temperature to optimize their strength and toughness. The N610/Si3N4-SiOC composites have the prior mechanical performance because the uniformly distributed Si3N4 matrix made the fiber bear effectively. After that, Sc-modified SiOC matrix was filled into inter- and intra-fascicular pores forming interfacial polarization, dipole polarization, multiple reflection and scattering to attenuate the incident electromagnetic wave (EMW). The effective absorption bandwidth (EAB) and the minimum reflection coefficient (RCmin) of N610/Si3N4-SiOC(Sc) composites at the thickness of 2.75 mm reaches 3.0 GHz and -42 dB in X band, respectively. In addition, the EMW absorption performance of the composite is relatively stable with EABmax and RCmin of 3.5 GHz and -41 dB in 4-18 GHz at high temperatures. This work provides a strategy for designing and fabricating OCMC with excellent mechanical properties and EMW absorption properties.