Effect of TiBCN Content on Microstructure and Properties of Laser Cladding Ti/TiBCN Composite Coatings

The Ti/TiBCN composite coatings were fabricated on the substrate of Ti6Al4V alloy by laser cladding. The effects of TiBCN content on the microstructre, microhardness, corrosion resistance and tribological properties of the composite coatings were studied. The results showed that, when the TiBCN content was 60 wt%, the composite coatings were mainly composed of the dendritic and rod-shaped TiBCN phases, small white lump TiC phases, fine lamellar TiN phases, small and scattered white block TiB₂ phases, In addition, there was a small quantity of short whisker Al₃Ti phases and uniform layer block TiAl phases. Furhtermore, the maximum microhardness was 1596 HV, which was about 4.6 folds greater than that of the substrate; the corrosion potential (E_corr) reached − 1.258 V and the corrosion current density (I_corr) was 4.035 × 10⁻⁵ A/cm², which was one order lower than that of the substrate (1.172 × 10⁻⁴ A/cm²); the worn surface was relatively smooth and the mass loss (1.22 g) was only 9/50 of that of the substrate (6.71 g).