WC reinforced Al-based coating with added CeO2 was prepared on the surface of S420 steel by laser cladding. The microstructure and structure of the coatings were analyzed by scanning electron microscope, X-ray diffractometer and optical profiler. The mechanical properties and corrosion properties of the coatings were studied by microhardness tester, friction and wear tester, Charpy impact tester, and electrochemical workstation. The results show that the coating is mainly composed of Al-phase, continuous-phase, and hard reinforced-phase WC, and the coating and substrate show good metallurgical bonding. When the content of CeO2 is 1%, the fine grain strengthening effect is obvious, and the impact toughness of the coating is obviously improved. Appropriate amount of rare earth CeO2 can significantly improve the hardness of the coating. When the content of CeO2 is more than 1%, the wear resistance of the coating decreases. The coating prepared with different CeO2 content has higher impedance and corrosion resistance than that of the substrate. At 1% CeO2 content, the coating has the best corrosion resistance.
Keywords: CeO2; S420 steel; corrosion resistance; impact toughness; laser cladding.