Calculation and synthesis of ZrC by CVD from ZrCl₄–C₃H₆–H₂–Ar system with high H₂ percentage

Highlights: • Suitable parameters for CVD ZrC using C₃H₆ with high H₂ percentage were calculated. • A smooth and dense ZrC coating was synthesized under calculation results. • Temperature, flux of C₃H₆ and H₂ significantly affect the synthesis of ZrC coating. • Deposition temperature using C₃H₆ was lower than using CH₄. - Abstract: A thermodynamic calculation about the synthesis of ZrC from the ZrCl₄–C₃H₆–H₂–Ar system with high percentage of H₂ was performed using the FactSage thermochemical software. According to the calculation, ZrC coating was synthesized on graphite substrates and carbon fibers by a low pressure chemical vapor deposition (LPCVD) process, and growth rate of the ZrC coating as a function of temperature was investigated. The surface diagrams of condensed-phases in this system were expressed as the functions of the deposition temperature, total pressure and reactant ratios of ZrCl₄/(ZrCl₄ + C₃H₆), H₂/(ZrCl₄ + C₃H₆), and the yield of the products was determined by the diagrams. A smooth and dense ZrC coating could be synthesized under the instruction of the calculated parameters. The morphologies of the ZrC coatings were significantly affected by temperature and gases flux. The deposition temperature is much lower than that from the ZrCl₄–CH₄–H₂–Ar system