Effect of high-energy carbon ion implantation on Ti–Al–Si–N coatings by metal vapour vacuum arc

Due to the combination of high hardness, good thermal stability and oxidation resistance, Ti–Al–Si–N coatings have become an excellent candidate for use as high speed machining coatings. Nowadays ion implantation has been employed to alter the near-surface structure and properties of semiconductors, metals and metal alloys without the loss of bulk properties. The present research investigated the effect of carbon ion implantation on the structural, mechanical and tribological properties of the Ti–Al–Si–N coatings prepared by reactive unbalanced magnetron sputtering. Carbon implantation was carried out by metal vapour vacuum arc ion source (MEVVA) with different carbon ion doses. After implantation, the samples were investigated systematically by means of the Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), cross-sectional transmission electron microscopy (TEM), X-ray photo-electron spectroscopy (XPS), surface profilometry (PGI), nano-indentation measurement and ball-on-disk test etc. The results showed that the implantation depth, chemical composition, microstructure and nanohardness depended strongly on the implanted carbon doses. In addition, a great improvement on the tribological performance was observed with the post-treatment process of carbon ion implantation.