Three composite coatings, CoCrNi-5TiB 2, CoCrNi-10TiB 2, and CoCrNi-15TiB 2, were successfully prepared on IN718 alloy by laser cladding with pre-placed CoCrNi-xTiB 2 powders (x = 5, 10, and 15 wt%). Their microstructures were thoroughly analyzed to understand their surface hardness and tribological performance. During laser cladding, the added TiB 2 powders are dissolved and then re-precipitate as fine and net-like TiB₂-type particles, along with particulate Cr₅B₃-type compounds. More TiB 2 additions lead to denser second phase particles (SPPs), enhanced element segregation and subgrain/grain refinement, and a higher frequency of ∑3 grain boundaries. The presence of ∑3 boundaries can be attributed to lattice distortion associated with the dense SPPs, reduced stacking fault energy due to element segregation, and localized in-situ heat treatment by adjacent laser tracks. The average hardness values of the CoCrNi-5TiB₂, CoCrNi-10TiB₂, and CoCrNi-15TiB₂ coatings are 412.3 ± 19.4 HV, 507.5 ± 24.9 HV, and 556.7 ± 15.7 HV, respectively, with corresponding wear rates of 2.5 × 10 −4 mm 3·N −1·m −1, 1.3 × 10 −4 mm 3·N −1·m −1, and 0.7 × 10 −4 mm 3·N −1·m −1. These coatings (particularly with more TiB 2 additions) exhibit much higher hardness and wear resistance than the IN718 substrate. Such superior surface performances could be attributed to joint strengthening contribution from high-density substructures and SPPs, enhanced element segregation, and more grain boundaries.