Long-term oxidation of MoSi₂-modified HfB₂–SiC–Si/SiC–Si coating at 1700°C

ABSTRACT

Slurry impregnation and gaseous Si infiltration were effectively used to produce compact MoSi₂-doped Si–HfB₂–SiC/Si–SiC (HMSS/SS) coatings with a thickness of 250 μm to protect carbon fibre reinforced carbon (C_f/C) composites from oxygen corrosion at 1700°C. The HMSS/SS coating obtained with a mosaic structure makes it possible to protect C_f/C composites at 1700°C for 276 h and the mass reduction is only 0.99%. The pinning effect of the embedded hafnia, the generated MoB together with the Hf, Mo co-doped Si-based glass layer, which successfully prevented the migration of oxygen, was attributed to the superior oxidation protection ability of the HMSS/SS coatings. This work provides a practical method for successfully extending the service life of C_f/C composites in the aerospace industry.

KEYWORDS:

• C_f/C composites
• coating
• slurry impregnation with gaseous Si infiltration
• oxidation behaviour at 1700°C
• mosaic structure
• pinning effect
• MoB
• protection mechanism

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 52125203], Science Center for Gas Turbine Project [grant number P2021-A-IV-003-001] and Fundamental Research Funds for the Central Universities [grant number G2022KY0616].