CAJ | 학술논문

The Fe-Cr-C flux-cored wires with 0 wt.%, 0.63 wt.%, 2.54 wt.% and 5.08 wt.% additions of nano-Y2O3 were developed in this work. And the different hypereutectic Fe-Cr-C hardfacing coatings were prepared. The phase structures of the coatings were determined by X-ray diffraction. The microstructures were observed by optical microscopy. The morphologies of the hypereutectic Fe-Cr-C hardfacing coatings were observed by a field emission scanning electron microscope equipped with an X-ray energy disper-sive spectrometer. The effectiveness of Y2O3 as heterogeneous nuclei of primary M7C3 was calculated with the misfit theory. The ex-periment results showed that, the microstructures of the hypereutectic Fe-Cr-C hardfacing coatings consisted of M7C3,γ-Fe andα-Fe phases. With the increase of nano-Y2O3 additives, primary M7C3 in hypereutectic Fe-Cr-C coatings could be refined gradually. The average size of the primary M7C3 was the minimum, which was 22μm, when nano-Y2O3 additive was 2.54 wt.%. The calculated re-sults showed that, the two-dimensional lattice misfit between the face (001) of Y2O3 and face (100) of orthorhombic M7C3 was 4.911%, which indicated that Y2O3 as heterogeneous nuclei of M7C3 was middle effective to refine the primary M7C3.