Abstract: Zirconium carbide (ZrC) coatings were deposited on graphite substrate at 1200°C by low pressure chemical vapor deposition (LPCVD) from the Zr-Br2-C3H6-H2-Ar system. The effect of total flow rate on the morphology and growth mechanism of ZrC coatings were investigated. As the total pressure increased, the deposition rate increased firstly and then decreased slowly, the maximum value was 3.37 g-3?cm-2?h-1. Meanwhile, the preferential orientation of ZrC coatings changed evidently, the (200) plane was the preferential orientation of ZrC coatings at the total flow rate of 600~800 ml/min. XPS showed that the C/Zr ratio of ZrC coatings increased from 0.85 to 1.49. At the total flow rate below 200 ml/min, the ZrC coatings were dense and composed of equiaxed gain structure. As the total flow rate increased from 400 to 800 ml/min, the ZrC coatings were well-faceted pyramidal-shaped crystals. When the total flow rate above 1000 ml/min, the ZrC coatings with a loose complex island-like gains. The variations of ZrC coatings can mainly be attributed to boundary layer with increasing the total flow rate.