Mechanical and microwave absorption properties of SiCf/SiC–Al4C3 composite with EPD-SiO2/ZrO2 interphase prepared by precursor infiltration and active filler-controlled pyrolysis method

Abstract

The SiO2/ZrO2 interphase was successfully prepared on SiC fibers by electrophoretic deposition (EPD) method and SiCf/SiC–Al4C3 composites were fabricated by precursor infiltration and active filler-controlled pyrolysis process using mixed PCS and aluminum fillers as precursors. The morphology of EPD-SiO2/ZrO2 interphase was observed by scanning electron microscopy (SEM) and its microstructure was characterized. The results indicated that a dense and smooth SiO2/ZrO2 interphase can be obtained by EPD method. The effects of EPD-SiO2/ZrO2 interphase on the mechanical, dielectric and microwave absorption properties of SiCf/SiC–Al4C3 composites were investigated. The flexural strength and fail displacement of SiCf/SiC–Al4C3 composite with 330 nm thick EPD-SiO2/ZrO2 interphase have been dramatically improved to 360 MPa and 0.58 mm, respectively, which were four times more than those of SiCf/SiC–Al4C3 composite without interphase. In addition, the complex permittivity of SiCf/SiC–Al4C3 composites were improved slightly from 6.8-3.5j to 8.5-3.9j at 10 GHz with the introduction of EPD-SiO2/ZrO2 interphase attributed to the inhibition of reaction between aluminum fillers and SiC fibers. Moreover, the introduction of EPD-SiO2/ZrO2 interphase has little influence on the microwave absorption properties of SiCf/SiC–Al4C3 composites and the effective microwave absorption band (RL ≤ −10dB) of SiCf/SiC–Al4C3 composites with EPD-SiO2/ZrO2 interphase reached to 3.9 GHz in X band according to the calculation values of reflection loss (RL), indicating its promising application in the field of structural and microwave absorption.