Effect of High-Energy Shot Peening on Properties of High-Velocity Oxygen-Fuel Spraying

Abstract

A Cr3C2-Al2O3-NiCr composite coating was prepared on an INCONEL600 alloy surface through high-velocity oxygen-fuel spraying followed by further processing through high-energy shot peening to create the composite coating. The microhardness and friction properties of the composite coating are analyzed by a microhardness tester and reciprocating friction tester. The microscopic structure and wear trace of the composite coating were analyzed by scanning electron microscope (SEM). The element distribution of the coating was analyzed by energy-dispersive spectroscopy (EDS). The porosity of the coating was detected by industrial CT. The phase and residual stress of the coating were tested by X-ray diffraction (XRD). The electrochemical corrosion and friction wear performance of the samples under different surface states were discussed. The results showed that the compactness of the coating was improved and the porosity was significantly reduced after high-energy shot peening. The high-energy shot peening did not alter the phase composition of the coating but introduced residual compressive stress. The microhardness of theCr3C2-Al2O3-NiCr high-velocity oxygen-fuel coating can reach 2.9 times that of the INCONEL600 substrate, and the hardness of the coating after high-energy shot peening can reach 3.9 times of that of the substrate. After high-energy shot peening, the corrosion resistance of the coating in HCl solution is improved. Compared with the INCONEL600 substrate, the friction coefficient and calculated wear rate of the Cr3C2-Al2O3-NiCr high-velocity oxygen-fuel coating decrease by 62.5% and 79.6%, respectively. After high-energy shot peening, the friction coefficient and calculated wear rate of the coating decrease by 75% and 98.7%, respectively.