Dual-Layer Oxidation-Protective Plasma-Sprayed SiC-ZrB2/ Al2O3-Carbon Nanotube Coating on Graphite

Ariharan, S and Sengupta, P and Nisar, A and Agnihotri, A and Balaji, N and Aruna, ST and Balani, K (2016) Dual-Layer Oxidation-Protective Plasma-Sprayed SiC-ZrB2/ Al2O3-Carbon Nanotube Coating on Graphite. Journal of Thermal Spray Technology, 26 . pp. 417-431. ISSN 1059-9630

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    Graphite is used in high-temperature gas-cooled reactors because of its outstanding irradiation performance and corrosion resistance. To restrict its high-temperature ([873 K) oxidation, atmospheric-plasma-sprayed SiCZrB2- Al2O3-carbon nanotube (CNT) dual-layer coating was deposited on graphite substrate in this work. The effect of each layer was isolated by processing each component of the coating via spark plasma sintering followed by isothermal kinetic studies. Based on isothermal analysis and the presence of high residual thermal stress in the oxide scale, degradation appeared to be more severe in composites reinforced with CNTs. To avoid the complexity of analysis of composites, the high-temperature activation energy for oxidation was calculated for the single-phase materials only, yielding values of 11.8, 20.5, 43.5, and 4.5 kJ/mol for graphite, SiC, ZrB2, and CNT, respectively, with increased thermal stability for ZrB2 and SiC. These results were then used to evaluate the oxidation rate for the composites analytically. This study has broad implications for wider use of dual-layer (SiC-ZrB2/Al2O3) coatings for protecting graphite crucibles even at temperatures above 1073 k

    Item Type: Journal Article
    Additional Information: Copyright to this article belongs to M/s. Springer
    Uncontrolled Keywords: oxidation;Plasma spraying;SiC;Sintering;ZrB2
    Subjects: CHEMISTRY AND MATERIALS > Composite Materials
    Division/Department: Other, Other, Other, Other, Surface Engineering Division, Surface Engineering Division, Other
    Depositing User: Ms. Alphones Mary
    Date Deposited: 08 May 2017 14:56
    Last Modified: 08 May 2017 14:56
    URI: http://nal-ir.nal.res.in/id/eprint/12541

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