Abstract:A bromination apparatus was designed and manufactured to accurately control the flow rate of ZrBr4 vapor. Zirconium carbide (ZrC) coatings were deposited on graphite substrate at 1200°C by low pressure chemical vapor deposition from the Zr-Br2-C3H6-H2-Ar system. The effects of gas composition (input C/Zr ratio) on the morphology and growth mechanism of ZrC coatings were investigated. The coating deposition process was controlled by the surface reaction kinetics at the input C/Zr ratio of 1.5, leading to a loose structure. When the input C/Zr ratios were 0.5 and 1, coating growth was dominated by diffusion kinetics, resulting in (200) preferential orientation with a dense columnar structure. Meanwhile, ZrC coating without free carbon was produced at the input C/Zr ratio of 0.5.