Thermodynamic Analysis of ZrB₂-SiC Oxidation: Formation of a SiC-depleted Region
A thermodynamic model was developed to explain the formation of a SiC-depleted layer during ZrB2-SiC oxidation in air at 1500°C. The proposed model suggests that a structure consisting of (1) a silica-rich layer, (2) a Zr-rich oxidized layer, and (3) a SiC-depleted zirconium diboride layer is thermodynamically stable. The SiC-depleted layer developed due to active oxidation of SiC. The oxygen partial pressure in the SiC-depleted layer was calculated to lie between 4.0 × 10−14 and 1.8 × 10−11 Pa. Even though SiC underwent active oxidation, the overall process was consistent with passive oxidation and the formation of a protective surface layer.
W. Fahrenholtz, "Thermodynamic Analysis of ZrB₂-SiC Oxidation: Formation of a SiC-depleted Region," Journal of the American Ceramic Society, American Ceramic Society, Jan 2007.
The definitive version is available at http://dx.doi.org/10.1111/j.1551-2916.2006.01329.x
Materials Science and Engineering
Keywords and Phrases
SiC-Depleted Region; Thermodynamic Analysis; ZrB2-SiC Oxidation
Article - Journal
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