Influence of Y₂O₃ addition amount on the microstructure and wide-temperature range tribological properties of wear-resistant and friction-reducing titanium-based coatings

This study fabricated Ti6Al4V/NiCr-Cr₃C₂/Ni-MoS₂/Y₂O₃ composite coatings via laser cladding technology, systematically investigating the effects of Y₂O₃ content (0–8 wt%) on microstructure and tribological properties across a wide temperature range (25–800 °C). Combining first-principles calculations with experimental characterization, we demonstrated that Y₂O₃ addition significantly improved coating formation quality, suppressed crack generation, and refined grain structure. The coatings primarily consisted of TiC, Ti₂S, Ti₂Ni, TiS₃, Y₂O₃ and β-Ti matrix. Results revealed that the 4 wt% Y₂O₃ coating exhibited optimal comprehensive performance: the room-temperature coefficient of friction decreased to 0.39 with a 23.1 % reduction in wear rate compared to the substrate, while at 800 °C the wear rate was merely 0.64 % of its room-temperature value with further significantly reduced coefficient of friction. First-principles calculations elucidated the strengthening mechanisms of TiC and Ti₂S as well as the self-lubricating characteristics of TiS₃, providing theoretical foundations for coating performance optimization. This research offers valuable insights for designing wear-resistant and friction-reducing coatings in aerospace applications.