Optimizing tribological properties of CrAlN coatings via Y doping over wide temperature range

: This study utilized high-throughput arc ion plating to deposit CrAlYN coatings (with 0.1-1.6 at. % Y) onto GH4169 substrates. The role of Y in regulating the tribological behavior of the coatings was systematically investigated across a temperature range of 25 to 800 °C. When Y content is 0.1 at. %, the coating exhibits optimal high-temperature performance at 800 °C, with COF of 0.39 and wear rate of 3.2×10 -6 mm 3 ·N -1 ·m -1 . This is attributed to the segregation of Y at the grain boundaries, which promotes the formation of a dense Cr 2 O 3 film, thereby enhancing lubricity. In contrast, at 800 °C, Y content of 1.6 at. % increases the surface roughness and triggers detrimental oxidation: excessive Y 2 O 3 forms layer that spalls under stress, generating abrasive debris and exacerbating wear, with the wear rate rising to 8.7×10 -6 mm 3 ·N -1 ·m -1 . At the same time, 0.3 at. % Y can enhance the mechanical properties of the coating, while higher Y content exceeds the structural stability threshold and accelerates oxidation kinetics. Crucially, in terms of tribological performance, CrAlY 0.1 N outperforms CrAlN coatings over the temperature range of 25 to 800 °C, indicates that precise Y doping is an effective way to optimize the friction-reducing and wear-resistant properties of coatings.