Improving Resistance to Crack and Corrosion of Laser-Cladded TiC/Co-based Composite Coatings by Doping Minor CeO2

Effects of CeO2 on the crack resistance and corrosion resistance of TiC/Co-based composite coatings are studied. The microstructure, morphology and element distribution, as well as the phase composition of the coatings were analyzed by optical microscope (OM), scanning electron microscope (SEM) and X-ray diffractometer (XRD), respectively. The results demonstrate that adding a small amount of CeO2 can make the microstructure of the coating more uniform and effectively improve the crack resistance and corrosion resistance of the coating. The addition of CeO2 can promote the dissolution of TiC particles in the original powder during laser cladding, and then re-nucleate with CeO2 as the nucleation sites, producing new refined TiC particles. In addition, the potentiodynamic polarization curves confirmed that with the increase in CeO2 content, the corrosion potential of the coating increased and the corrosion current decreased, indicating that the corrosion resistance of coating was increased.