Microstructure and Wear Resistance of a Cr7C3 Reinforced Ni3Al Composite Coating Prepared by Laser Cladding

Abstract

Using Cr7C3/Ni3Al alloyed powder and Cr3C2/Ni3Al mixed powder, laser cladding was carried out to prepare a Cr7C3 reinforced Ni3Al composite cladding layer. The microstructure and tribological properties of the cladding materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and wear tests. The results indicate that the microstructure of the Cr7C3/Ni3Al alloyed powder cladding layer contains mainly Ni3Al, NiAl, and in situ-formed Cr7C3, whereas Cr3C2 occurs in the Cr3C2/Ni3Al mixed powder cladding layer. The friction coefficient and wear loss of the alloyed powder cladding layer are about 0.1 and 0.75 mg, respectively, which are less than those of the mixed powder cladding layer (0.12 and 0.8 mg). Moreover, the alloyed powder cladding layer is much friendlier to its counterpart. The counterpart’s loss weight of the alloyed powder cladding layer decreases 42.2% than the mixed powder cladding layer. The reason can be attributed to the homogeneous distribution of fine in situ-formed Cr7C3 in the alloyed powder cladding materials, which can effectively separate the friction pair, improving the wear resistance of the cladding materials.