Influence of CeO2 on the microstructure and wear resistance of iron-based alloy coating studied by Rietveld refinement method

Iron-based alloys containing 0 wt.% and 3 wt.% CeO2 (CeO2-free and CeO2-modified, respectively) particles were deposited on Q235 low carbon steel using plasma transferred arc (PTA) welding machine. Microstructures of the two coatings were studied by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM) with energy dispersive X-ray energy spectrometer (EDS), and transmission electron microscope (TEM). More details about the phase compositions and abundance of the deposited coatings were obtained with the application of the Rietveld refinement method to analyze XRD patterns. Wear resistance experiment was conducted on one dry sand abrasion test (DSAT) machine to value the coatings. The results show that the CeO2-free coating consists of γ (Fe, Ni), (Cr, Fe)7C3, and (Cr, Fe)2B phases. Comparing with the CeO2-free coating, adding 3 wt.% CeO2 not only leads to appear CeO2 phase except for those phases that existed in CeO2-free coating, but increases the relative contents of the total Cr-rich compounds by 14.8%, and refines the microstructure of the iron-based alloy coating. The microstructure change, the variation in phase compositions and abundance are responsible for increasing the abrasive wear resistance of the CeO2-modified iron-based alloy coating.