Phase composition, microstructure and mechanical properties of ZrC coatings produced by chemical vapor deposition

We report results on stoichiometric and non-stoichiometric ZrC coatings produced on graphite substrates by chemical vapor deposition (CVD) in the ZrCl4–CH4–Ar system. The phase composition, microstructure and mechanical properties of both (ZrC and ZrC0.85) coatings were studied. X-ray diffraction (XRD) confirmed the formation of cubic ZrC. A strong (200) texture normal to the substrate surface was observed in both coatings which were confirmed by scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) showed ZrC to be the main phase in both coatings with ∼5.5 mol% ZrO2 minor phase. In stoichiometric ZrC coating, both Young's modulus (312±9 GPa) and hardness (25±3.1 GPa) were higher compared to the non-stoichiometric ZrC0.85 coating.