Stability of SiC and SiO₂ in Helium with Little Water Vapor

Abstract:

The stability of SiC and SiO₂ in helium with little water vapor is studied in this paper in order to confirm whether they can service as anti-oxidation layers on the surface of fuel elements of high temperature gas-cooled reactor (HTR) under water-ingress accident. Through thermodynamic analysis, it is found that the influence factor controlling the critical temperature of passive oxidation for SiC in He-H₂O is the partial pressure of H₂O; the critical temperature of passive oxidation for SiC increases with the partial pressure of H₂O. The influence factors controlling the critical temperature of decomposition for SiO₂ are the partial pressure of H₂O and the amount of H₂O in gas for 1 mol SiO₂, the critical temperature of decomposition for SiO₂ increases with the partial pressure of H₂O while it decreases with the amount of H₂O in gas for 1 mol SiO₂. SiO₂/SiC composite coating is more suitable than SiC coating in He-H₂O with little H₂O.

• Periodical: Advanced Materials Research (Volumes 1030-1032)
• Pages: 276-279
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1030-1032.276
• Online since: September 2014
• Authors: Zhi Qiang Fu*, Wen Yue, Cheng Biao Wang, Chun He Tang
• Keywords: Helium-Water Vapor, High Temperature Stability, Silicon Carbide (SiC), SiO₂, Thermodynamic Analysis

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