Effect of CeO₂ Addition Amount on Microstructure and Properties ofLaser Cladded TiB₂-TiC/Ni Composite Coating

The TiB₂-TiC/Ni composite coating added with 1wt%, 1.5wt% and 2wt% CeO₂ was prepared on the surface of TC4 titanium alloy by laser cladding technique. The phase composition, microstructure, and hardness of the composite coating were studied, and the effect of lapping rate (30%, 40%, 50%) on the friction and wear properties of the composite coating sample under the optimal CeO₂ content condition was discussed. The results show that the composite coating consisted of TiB₂, TiB, α-Ti, TiC, Ni₃Ti, Cr₂₃C₆, Ti₂Ni, Cr₃C₂ and γ-Ni phases. The microstructure of the composite coating added with 1.5wt% CeO₂ was the most uniform and dense, and the refinement effect was obvious. With the increase of CeO₂ addition amount, the hardness of the composite coating increased first and then decreased. The hardness of the composite coating added with 1.5wt% CeO₂ was the highest of about 1 015 HV. The optimal mass fraction of CeO₂ was 1.5%; under this condition, the wear mass loss of the sample decreased first and then increased with the increase of lapping rate. When the lapping rate was 40%, the wear mass loss was the smallest, and the wear mechanism was abrasive wear.