Effects of CeO2 on the Microstructure and Properties of Laser Cladding 316L Coating

Laser cladding was used to distribute a CeO2-modified 316L powder coating onto a 316L stainless steel surface. The cladding layer phase composition was evaluated through x-ray diffraction. An analysis of the microstructure was conducted using an optical microscope and scanning electron microscope, while the micro-hardness was measured using a tester. The coating corrosion behavior in response to 3.5% NaCl solution was analyzed by polarization curves and electrochemical impedance spectroscopy. Finally, the overall performance of coatings with different CeO2 concentrations, 1, 2, and 3%, was compared. Results showed that adding CeO2 significantly refined the grains, reduced the coating porosity, and effectively limited the appearance of local corrosion. Also, additive CeO2 shifted the coating’s electrode potential in a positive direction, minimizing the current density of corrosion, creating a stable passivation film, and improving the coating’s corrosion resistance. The coating performance (hardness and corrosion behavior) was optimal when 2% CeO2 was employed as the powder mass.