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This paper aims to experimentally investigate the effect of graphene nanoplatelets (GNPs) doped Al2O3 coating deposited on the surface of cemented carbide substrate using suspension high velocity oxy fuel (SHVOF) thermal spraying technique. Scanning electron microscopy was applied to characterize GNPs doped Al2O3 feedstock, the surface morphologies of cemented carbide before and after spraying, and the wear track morphology of cemented carbide after wear tests. The phases of GNPs doped Al2O3 feedstock, uncoated and coated cemented carbide were analyzed by X‐ray diffraction. The existence of GNPs was analyzed by Raman spectroscopy. A mixture of un‐molten and molten splats formed on the surface of cemented carbide substrate after SHVOF thermal spray. The average coefficient of friction (CoF) of coated samples was slightly lower than that of uncoated samples, which might be due to the friction‐reduction effect of GNPs. The wear rate of the samples was one order of magnitude higher than that of the alumina ball, showing that the wear of samples was the main wear between the friction couples. The wear mechanism of uncoated sample was mainly fatigue spalling, and that of cemented carbide substrate coated with GNPs doped Al2O3 coating was mainly plowing and abrasive wear. [ABSTRACT FROM AUTHOR]

Grid and line textures were made on the top surfaces of WC-TiC-Co cemented carbide substrates. Suspension High Velocity Oxy-Fuel (SHVOF) was utilized to deposit alumina and graphene nanoplatelets (GNPs) coating on the textured surfaces. The friction and wear behaviors of the Alumina/GNPs coating were evaluated using dry sliding wear tests against alumina balls. The friction reduction mechanism of alumina/GNPs coating was presented. GNPs in the alumina coatings played a significant role in reducing the coefficient of friction (CoF) up to 40 % and improving the wear resistance properties of the coating. A stress distribution model of the friction contact zone was provided to analyze the tribological performance of the textured sample. The friction reduction mechanism for alumina/GNPs coating was discussed. These results offer a benchmark for further studies combining microtextured surfaces and SHVOF thermal sprayed coatings as promising candidates for high wear resistant applications. • The stress distribution model of the friction contact zone was provided. • A wear mechanism for GNPs doped Al 2 O 3 coatings was proposed. • A thin, controlled layer which preserved the texture surface morphology was formed. [ABSTRACT FROM AUTHOR]