The Influence of SiO2 + SiC + Al (H2PO4)3 Coating on Mechanical and Dielectric Properties for SiCf/MWCNTS/AlPO4 Composites

Yan Zhu; Feng Wan; Jianhui Yan; Hongmei Xu

doi:10.3390/ma15155178

The Influence of SiO₂ + SiC + Al (H₂PO₄)₃ Coating on Mechanical and Dielectric Properties for SiC_f/MWCNTS/AlPO₄ Composites

Materials (Basel). 2022 Jul 26;15(15):5178. doi: 10.3390/ma15155178.

Authors

Yan Zhu^{1

2}, Feng Wan^{1

2}, Jianhui Yan^{1

2}, Hongmei Xu^{1

2}

Affiliations

¹ School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China.
² Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion, Hunan University of Science and Technology, Xiangtan 411201, China.

Abstract

SiC fiber-reinforcedAlPO₄ matrix (SiC_f/MWCNTs/AlPO₄) composites were fabricated using a hot laminating process with multi-walled carbon nanotubes (MWCNTs) as the absorber. A coating prepared from SiO₂ + SiC + Al (H₂PO₄)₃ was applied to the surface of the SiC_f/MWCNTs/AlPO₄ composites prior to an anti-oxidation test at 1273 K in air for 40 h. The anti-oxidation effect was verified by a three-point bending test, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and a dielectric property test. Anti-oxidation mechanism investigations revealed that the coating effectiveness could be attributed to three substances, i.e., SiO₂, SiP₂O₇_, and SiO₂ +AlPO₄ solid solution from the reactions of SiC + O₂→SiO₂ + CO, SiO₂ + P₂O₅→SiP₂O₇ and SiO₂ +AlPO₄→solid solution, respectively.

Keywords: SiC fibers; SiP2O7; oxidation; solid solution.

Abstract

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