Effect of Heat Treatment on Microstructure and Tribological Properties of Laser Cladding CeO2/Ni60 Composite Coating on 35CrMoV Steel

Abstract

A Ni60 cladding layer with addition of 6.0% CeO2 was prepared on 35CrMoV steel by laser cladding technology. The prepared sample was placed at 500 °C, 600 °C and 700 °C for 60 min to explore the effects of heat treatment on the tribological properties of the composite coating. The microstructure, phase composition, microhardness and tribological properties of the composite coating were characterized by optical microscopy and scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-Vickers hardness tester and MicroXAM-800 optical surface photometer, respectively. According to the above experimental results analysis, the main components of 6.0% CeO2/Ni60 cladding layer are γ-(Fe,Ni),Cr7C3,Cr23C6,CrB, CrFeB and Cr2Ni3. By calculating the FWHM value and the left shift of the XRD diffraction peak, it is found that the coating grains are remarkably refined and the microstructure uniformity is significantly improved under the condition of heat treatment at 500 °C. The experimental results show that the Ni60 composite coating with 6.0% CeO2 has the best friction and wear performance at 500 °C. The wearing quality of the composite coating at 500 °C was reduced by 43%.