EFFECT AND MECHANISM OF CeO2 ON THE MICROSTRUCTURE AND PROPERTIES OF Ni60A–Cr3C2 LASER CLADDING LAYER

Using laser cladding technology, a Ni60A alloy cladding layer added with rare earth oxides CeO2 and Cr3C2 was prepared on the surface of Cr12MoV die steel. Through scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) analyses, the influence of CeO2 on the microstructure, hardness and wear resistance of Ni60A–Cr3C2 laser cladding layer was studied, and the mechanism of action of CeO2 was discussed. The results show that in the laser cladding Ni60A–Cr3C2 coating, after adding CeO2 powder, the cladding layer is well formed and the microstructure is significantly refined. As the addition of CeO2 increases, the microhardness of the cladding layer increases first and then decreases. When the addition amount of CeO2 is 2wt.%, the microhardness of the coating is the largest, which is 1107HV. As the content of CeO2 continues to increase, the hardness decreases. As the content of CeO2 in the cladding layer increases, the wear loss of the sample first decreases and then increases. When the mass fraction of CeO2 is 1wt.%, the wear loss of the cladding layer is the least and the wear resistance is the best. The wear morphology of the Ni60A+Cr3C2 cladding layer without adding CeO2 appears with a lot of abrasive debris, and the main mechanism is adhesive wear. When the addition amount of CeO2 is 1wt.%, the wear mainly appears as furrow, which denotes abrasive wear.