Microstructure and mechanical properties of hafnium carbide coatings synthesized by reactive magnetron sputtering

Abstract

Hafnium carbide coatings with different carbon contents were synthesized in Ar–C₂H₂ mixture by reactive magnetron sputtering. Energy-dispersive X-ray, X-ray diffraction, scanning electron microscopy, atomic force microscopy, and nanoindentation were employed to characterize their microstructure and mechanical properties. The effects of C₂H₂ partial pressure on the composition, phase, microstructure, and mechanical properties of the coatings were investigated. The results show that hafnium carbide coatings can be synthesized at a low partial pressure of C₂H₂. The single-phase HfC coating with columnar crystal and favorable mechanical properties is obtained when the proportion of C₂H₂ partial pressure is only about 3.0% in the mixture, and the highest hardness and modulus are 27.9 and 255 GPa, respectively. The coating contains metal Hf and HfC phases and obtains low hardness under lower C₂H₂ partial pressure. When the C₂H₂ partial pressure is higher, the hardness and elastic moduli of acquired amorphous coatings decrease significantly.