The MCrAlX coatings, including NiCrAlY and NiCoCrAlYHfSi coating, were successfully deposited on 316L stainless substrate by high velocity oxy-fuel (HVOF) spraying. The microstructure, phase composition and mechanical properties of the coatings were investigated in detail. The tribological performance of the coatings servicing at 25 °C, 200 °C, 400 °C, 600 °C and 800 °C was mainly measured. The effect of the doping of alloying elements, such as Co, Hf and Si, in NiCrAlY coating on its microstructure as well as mechanical and tribological performance was investigated to reveal the wear resistance mechanism of the NiCrAlY and NiCoCrAlYHfSi coatings. The results reveal that both of coatings exhibit a dense and uniform structure, with a porosity of less than 2 %. The double kinds of coatings mainly contain γ-Ni, β-NiAl, γ′-Ni 3Al phases and a bit of α-Al 2O 3, but there is a widen phenomenon of main XRD diffraction peaks. This is because the crystals deform or incompletely grow due to the high residual stress or instantly cooling during deposition. At room temperature, the mechanical properties of NiCoCrAlYHfSi coating are better, compared to NiCrAlY coating. However, with the elevated temperatures, the micro-hardness of NiCrAlY coating is higher, except for at 800 °C. The coefficient of friction (COF) of both of the coatings gradually decreases with the elevated temperatures. The NiCoCrAlYHfSi coating possesses a lower wear rate, apart from at 200 °C. The oxides, including aluminum oxide (Al₂O₃), chromium oxide (Cr₂O₃), nickel oxide (NiO), and nickel chromite (NiCr₂O₄), could be found on the worn surface. During friction, multiple tribochemical reactions occur, resulting in the formation of various oxides on the worn surface. The continuous and dense glazed layer by in-situ reaction during friction is the main factor that coatings demonstrate excellent tribological properties under high temperature.
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