Impact of HVOF Regimes on the Structure, Phase Composition, and Mechanical and Tribological Properties of 86WC–10Co–4Cr Coatings

The aim of this work is to investigate the influence of high-velocity oxygen-fuel spraying (HVOF) process regimes on the microstructure, phase composition, and mechanical and tribological properties of 86WC–10Co–4Cr coatings on a 12Kh18N10T stainless steel substrate. The coatings were formed under three HVOF spraying regimes, differing in oxygen and fuel flow rates. The study included microstructure (SEM), elemental composition (EDS), phase composition (XRD) analysis, instrumental indentation, confocal laser profilometry, and tribological tests using the ball-on-disk scheme under dry friction conditions. It was found that all coatings are characterized by a dense structure, low areal porosity of about 1.4%, and a relatively uniform distribution of the main elements. X-ray phase analysis confirmed the predominance of WC with the formation of an insignificant amount of W2C due to limited decarburization. The instrumented indentation hardness (HIT) ranged from 13.03 to 13.56 GPa, and the elastic modulus ranged from 334.4 to 342.0 GPa. The maximum hardness was obtained for C1 (13.56 ± 0.58 GPa), and the maximum modulus was for C3 (342 ± 19.1 GPa). The Ra values ranged from 2.8 to 4.19 μm. Tribological tests revealed differences in the mean wear values among the spraying regimes; however, these differences were not statistically significant (p = 0.921). The results obtained can serve as an experimental basis for selecting promising HVOF processes for the hardening and restoration of components used in pumping, mining, and metallurgical equipment; their operational effectiveness must be further confirmed under actual industrial conditions.