Effect of CeO₂ on microstructure and properties of Fe-based coating produced by plasma arc cladding process

The effect of addition of 1% CeO₂ on the microstructure and wear resistance of high chromium cast iron coating produced by plasma arc cladding process was investigated by means of optical microscope(OM), scanning electron microscope(SEM), X-rays diffraction(XRD) and sliding wear testing. The results show that the phases composition of the alloy coating compared with the Fe-iron coating was not changed, both consisted of γ-(Ni, Fe) solid solution with a face-centered cubic lattice and M₇C₃(M=Cr, Fe, Mo) carbides with a hexagonal structure. Heterogeneous nucleation of the alloy coating modified with rare earth oxide CeO₂ that leads to the microstructure refinement and restrains the growth of carbides. And it changes the crystal growth direction of γ-(Fe, Ni) solid solution from both 111 and 002 to single 002. Meanwhile, the rare earth oxides homogeneously distribute in eutectic microstructure, thus improving the microhardness and wear resistance of the coating.