Optimization of CVD SiC process and preparation of high-purity coatings based on a thermodynamic-fluid dynamics coupled model

• A coupled thermodynamic-fluid dynamics model significantly improves prediction accuracy for CVD SiC deposition compared to thermodynamics alone. • Low-temperature silicon-rich deposition is attributed to low CH4 reactivity and preferential chlorosilane adsorption, while high-temperature stoichiometric SiC formation is driven by SiCl2 and C2H2 as dominant precursors. • The model enables precise control of CVD parameters to achieve high-purity, stoichiometric SiC coatings, crucial for aerospace and nuclear applications. • This integrated approach compensates for thermodynamic calculation limitations and provides a reliable theoretical basis for industrial SiC coating optimization.