Application of CFD simulation to silicon carbide deposition for nozzles with funnel
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ORIGINAL ARTICLE
Application of CFD simulation to silicon carbide deposition for nozzles with funnel Jin‑Won Seo1 · Kyoon Choi1 Received: 3 August 2020 / Revised: 3 September 2020 / Accepted: 8 September 2020 © The Korean Ceramic Society 2020
Abstract Carbon/silicon carbide composites (C/SiC) have been extensively studied for structural components in extreme environments because of their excellent thermal shock resistance and specific strength at high temperatures. In order to overcome their oxidizing problems, chemical vapor deposition (CVD) coating of silicon carbide to C/SiC has become an important technical issue especially for the specific shapes such as nozzles and pipes that withstand supersonic flows of exhaust gases and particles. The growth rate prediction based on the CFD simulation was carried out to effectively coat the inner surface of a nozzle. For the inner coating of nozzels, a funnel that guides the reaction gases to the nozzles was introduced in order to accelerate the SiC coating. As the CFD simulation predicted, the growth rate of silicon carbide with the funnel is 5 times higher than that without the funnel. Keywords Silicon carbides · Chemical vapor deposition · Anti-ablation · CFD simulation
1 Introduction Silicon carbide (SiC), which is well known for its high hardness and its superior strength and oxidation resistance at high temperature, is increasingly used for extreme environment applications such as electrodes and focus rings in plasma ion etchers [1] and engine components for space vehicles [2]. In particular, this structural ceramic is getting more attention due to its easy and robust junction with isotropic carbons. Furthermore, silicon-carbide films can be easily deposited on carbon substrates by using chemical vapor deposition (CVD) processes. These SiC-coated carbon components can be used in the semiconductor industry due to their dust-suppressing capability on their surfaces. The components also exhibit extremely good resistance to wear and to corrosion by acids and bases. The CVD process of silicon carbide is conducted in a hot-wall chamber equipped with a bubbler that contains CH3SiCl3 (methyltrichlorosilane, MTS) as a source material [3]. The saturated hydrogen gas flows into the chamber, which results in the deposition of SiC on the carbon
* Kyoon Choi [email protected] 1
components through the thermal decomposition of MTS. Residual gases such as hydrogen and various types of chlorides can be pumped out. The overall process can be summarized in the following equation:
CH3 SiCl3 + x H2 = SiC + 3 HCl + x H2 .
(1)
In order to predict the precise reactions included in the SiC deposition, Kim et al. [3] and Choi et al. [4] proposed that the thermodynamic predictions of the deposited phases based on the thermodynamic database could provide good explanations regarding the solid phases in the various pressure, temperature, and compositional ranges of the deposition conditions. However, the deposition process of SiC includes numerous gas-phase reactions and the followi
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