An Innovative VCN Coating for High-Temperature Tribological Applications via Orthogonal Research

Abstract

An innovative vanadium carbonitride coating with C element doped in a vanadium nitride (VN) matrix was developed on Inconel 718 and Si (100) substrates using a multi-arc ion plating technique. The micromorphology and microstructure of the as-deposited VCN coating were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results show that the incorporation of C-dopant with the VN matrix can produce both sp2 C-C and sp3 C-C hybridized structures besides VC and VN phases. Furthermore, tribological testing was performed on a ball-on-disc tribometer with an Al2O3 ball as the counterpart. The main mechanisms of friction factors and C-dopant that affect the tribological properties of VCN coating were studied under some designed orthogonal parameters. The optimal solutions for VCN and VN coatings to attain the lowest friction coefficient and wear rate were suggested by orthogonal analysis, and the order of importance of friction factors that influence the tribological performance of VCN and VN coatings was clarified for each situation. In addition, the lubricant mechanisms of sp2 hybridized carbon and V2O5 crystal were focused on due to their special graphite-like structure as well as Magnéli phase, which can enhance the antiwear and antifriction effect of VCN coating under test conditions. Finally, the wear morphologies of all tested samples were observed by SEM, and the phase composition in the worn area was investigated by micro-Raman spectrometry.