Influence of CeO₂ on Microstructure and Microhardness of TiC₄ Coating Produced by Laser-Cladding

TiC4 ceramic layer modified by CeO2 was deposited on 45 steel substrate by laser-cladding technique.The phase composition,microstructure and microhardness of the clad coating were analyzed by SEM,XRD and micro-hardness tester.The results show that the TiC4 ceramic coating prepared by laser-cladding method had typical surrounding phase and hard spot phase structure.Density of the coating was improved,TiC4 particle size was less than 1 μm and the average micro-hardness increased to 700 MPa when 0.3wt%-1.0wt% CeO2 was added.Adding exccess (≥1.5wt%) CeO2 would make adverse effect on the coating micro-hardness,i.e.,the surrounding phase content and TiC4 particle size increased,and the TiC4 grain was lance-shaped and the micro-hardness decrased to 450 MPa.