Study on microstructure and friction and wear properties of wear-resistant coatings prepared by thermal spraying

Abstract

In this paper, Cr2O3-2TiO2 and Al2O3 coatings are prepared by atmospheric plasma spraying (APS), and WC-10Co4Cr was prepared by high velocity oxygen fuel (HVOF). The powders and coatings are characterized with scanning electron microscopy (SEM) and energy dispersive spectrometry. X-ray diffraction (XRD) is used to qualitatively analyze the phase. The generation of new material is analyzed. The Vickers hardness of each coating is tested by microhardness tester. The tribological properties of the coatings are tested with the multifunctional material surface tester and the friction coefficient curves are drawn with the collected data. It is found that the friction and wear properties of the Cr2O3-2TiO2 coating are good due to the high degree of flattening during spraying. Cr2O3-2TiO2 coating has the highest average hardness. The phase structure is stable before and after spraying. Compared with the powder, the X-ray diffraction peaks of Al2O3 coating are seriously widened, some diffraction peaks are offset, and the intensity of the derived peaks is significantly reduced. Al2O3 coating has the largest hardness and lowest average hardness. However, compared with the other two coatings, Al2O3 coating has the worst wear resistance. It is also found that decarburization occurred during HVOF of WC-10Co4Cr. However, CoCr phase will wrap the WC, which can greatly reduce decarburization of WC during spraying. The bonding strength, wear resistance and toughness of the coating will be significantly enhanced. Compared with Al2O3 coating and Cr2O3-2TiO2 coating, the wear resistance of WC-10Co4Cr coating is slightly better.