Review of rare earth oxide doping-modified laser cladding of Fe-based alloy coatings

Conventional Fe-C alloy parts used in mechanical transmission and braking systems exposed to the external environment often suffer from wear and corrosion failures. Surface coating strengthening technologies have been explored to improve the surface performance and prolong service life of these parts. Among these technologies, laser cladding has shown promise in producing Fe-based alloy coatings with superior interfacial bonding properties to the Fe-C alloy substrate. Additionally, the microstructure of the Fe-based alloy coating is more uniform and the grain size is finer than that of surfacing welding, thermal spraying, and plasma cladding, and the oxide film of alloying elements on the coating surface can improve the coating performance. However, Fe-based alloy coatings produced by laser cladding typically exhibit lower hardness, lower wear resistance, corrosion resistance, and oxidation resistance compared to coatings based on Co and Ni alloys. Moreover, these coatings are susceptible to defects such as pores and cracks. To address these limitations, the incorporation of rare-earth oxides through doping in the laser cladding process has garnered significant attention. This approach has demonstrated substantial improvements in the microstructure and properties of Fe-based alloy coatings. This paper reviewed recent research on the structure and properties of laser-cladded Fe-based alloy coatings doped with various rare earth oxides, including La2O3, CeO2, and Y2O3. Specifically, it discussed the effects of rare earth oxides and their concentrations on the structure, hardness, friction, wear, corrosion, and oxidation characteristics of these coatings. Furthermore, the mechanisms by which rare earth oxides influence the coating’s structure and properties were summarized. This review aimed to serve as a valuable reference for the application and advancement of laser cladding technology for rare earth modified Fe-based alloy coatings.