Mo alloying enhances AlTiN coatings, yet the trade-offs among mechanical, oxidation, wear, and cutting performance with varying Mo content remain inadequately understood. We investigate AlTiMoN coatings with 0–15.1 at.% Mo deposited by HiPIMS. All coatings maintain a face-centered cubic structure. Mo addition refines grains and densifies microstructure, but higher Mo levels induce nitrogen vacancies and Mo₂N precipitation. Hardness peaks at 35.5 GPa with 3.4 at.% Mo, whereas fracture toughness decreases with Mo content. Mo transforms the oxide scale from a bilayered Al₂O₃/TiO₂ structure into a dense, Al-rich scale, reducing thickness from ~540 nm to ~165 nm at 850 °C. Mo forms a lubricious tribofilm that lowers the friction coefficient from 0.66 to 0.51, reducing the wear rate by two orders of magnitude to 3.49 × 10⁻⁸ mm³/(N·m). At 800 °C, AlTiMoN_1# shows the lowest wear rate of 1.33 × 10⁻⁵ mm³/(N·m), while excessive Mo addition leads to higher wear rates than Mo-free AlTiN due to mechanical degradation and MoO₃ volatilization. Turning tests confirm that Mo-containing tools exhibit suppressed crater wear and thermal deformation, extending tool life, with AlTiMoN_1# achieving the best performance. This work establishes a comprehensive composition–performance relationship for AlTiMoN coatings and offers design guidelines for advanced nitride coatings.
 

AlTiMoN coatings; HiPIMS; Oxidation; Wear resistance; Cutting performance