Wear behaviour of wear-resistant adaptive nano-multilayered Ti-Al-Mo-N coatings

•Nano-multilayered Ti-Al-Mo-N coatings were deposited by the arc-PVD method.•Changes in the coating deposition parameters lead to different phase composition.•The hardness of the obtained Ti-Al-Mo-N coatings was up to 40GPa.•(Ti,Al)N-Mo2N coating demonstrated better mechanical properties than (Ti,Al)N-Mo-Mo2N.•Mo oxide phases formed during friction reducing friction coefficient at 20–500°C. Coating samples in the Ti-Al-Mo-N system were obtained by arc-PVD method at variable bias voltage Ub applied to the substrate, and the partial pressure of nitrogen P(N2) used as a reaction gas. The deposited coatings were characterized by a nanocrystalline structure with an average grain size of 30–40nm and multilayered architecture with alternating layers of (Ti,Al)N nitride and Mo-containing phases with a thickness comparable to the grain size. Coatings of (Ti,Al)N-Mo-Mo2N and (Ti,Al)N-Mo2N compositions were obtained by changing deposition parameters. The obtained coatings had hardness of 40GPa and the relative plastic deformation under microindentation up to 60%. (Ti,Al)N-Mo2N coatings demonstrated better physicomechanical characteristics, showing high resistance to crack formation and destruction through the plastic deformation mechanism without brittle fracturing, unlike (Ti,Al)N-Mo-Mo2N. The friction coefficient of the study coatings (against Al2O3 balls under dry condition using a pin-on-disc method) reached the values of 0.35 and 0.5 at 20°C and 500°C respectively, without noticeable wear within this temperature range. These tribological properties were achieved by forming MoO3 acting as a solid lubricant. At higher temperatures the deterioration in the tribological properties is due to the high rate of MoO3 sublimation from friction surfaces.