Acta Metallurgica Sinica (English Letters) ›› 2023, Vol. 36 ›› Issue (11): 1909-1923.DOI: 10.1007/s40195-023-01596-7

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Mechanical Properties and Oxidation Behaviors of Self-Healing SiCf/SiC-SiBCN Composites Exposed to H2O/O2/Na2SO4 Environments

Suya Ji1,2, Bin Liang1(), Chenglong Hu1, Shengyang Pang1, Rida Zhao1, Jian Li1, Sufang Tang1()   

  1. 1Shi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
    2School of Materials Science and Engineering, University of Science and Technology of China, Shenyang, 110016, China
  • Received:2023-03-14 Revised:2023-05-11 Accepted:2023-05-31 Online:2023-11-10 Published:2023-08-23
  • Contact: Bin Liang, bliang@imr.ac.cn; Sufang Tang, sftang@imr.ac.cn

Abstract:

The oxidation behaviors and their influence on the mechanical properties of self-healing SiCf/SiC-SiBCN composites were investigated in H2O/O2 and H2O/O2/Na2SO4 environments at 1200‒1350 °C for 100 h. As the temperatures increase from 1200 to 1350 °C, the oxidation rate constants increase from 0.45 × 10-7 to 1.58 × 10-7 mg2/(mm4 h) in H2O/O2, and from 1.02 × 10-7 to 3.42 × 10-7 mg2/(mm4 h) in H2O/O2/Na2SO4. The involvement of Na2SO4 leads to the formation of a loose lamellar oxide layer, the breakage of the SiBCN/CVI-SiC interface and the decrease in the oxide viscosity, thus accelerating the oxidation of the composites. The composites show the maximum retention rate of strength (102%, 535.71 MPa) after oxidation in H2O/O2 at 1200 °C due to the good self-healing capacity of the produced glass, while the minimum (82%, 430.56 MPa) in H2O/O2/Na2SO4 at 1350 °C caused by the severe microstructural corrosion derived from Na2SO4.

Key words: SiCf/SiC-SiBCN composite, Mechanical property, Oxidation, Chemical vapor infiltration and polymer infiltration and pyrolysis (CVI-PIP), Self-healing