Enhanced wet-oxidation resistance of Y2O3 modified SiC ceramics by the formation of Y2Si2O7 protective layer.

The poor wet-oxidation resistance limits the long-life service of SiC f /SiC composites as the hot end components of aero-engines. The stability of SiC f /SiC composites under high-temperature wet oxygen environment can be promoted by more robust SiC matrix. In this work, the effect of Y 2 O 3 on the corrosion behaviors of SiC ceramics in flowing O 2 /H 2 O atmosphere at 1400 ℃ was studied. Duo to the continuous Y 2 Si 2 O 7 layer formed on the surface, SiC-Y 2 O 3 ceramics exhibit much better wet-oxidation resistance than original SiC ceramics. During the oxidation process, Y 2 O 3 dispersed in the ceramics migrates to the surface and reacts with SiO 2 to form β-Y 2 Si 2 O 7. Subsequently, the β-Y 2 Si 2 O 7 aggregates and grows to form a continuous Y 2 Si 2 O 7 layer, inhibiting the corrosion from oxidizing medium to the inner SiC matrix. This study is expected to provide important ideas for the design and structure regulation of wet-oxidation resistant SiC f /SiC composites. [ABSTRACT FROM AUTHOR]