Structural evolution and high-temperature tribological properties of AlCrON coatings deposited by multi-arc ion plating

AlCrON coatings were deposited on plasma nitrided steel substrates by multi-arc ion plating under different oxygen flow rates. The surface morphology, structure, composition, mechanical properties, and tribological behavior were investigated systematically. The coating surface roughness increases with increasing oxygen flow rate. The structural analysis show as-deposited coatings exhibit B1 NaCl like solid solution phases, transformed from fcc-(Cr, Al)N to fcc-(Cr, Al)ON followed by fcc-(Cr, Al)2O3 phase structure for coating deposited at the oxygen flow rate of 300 sccm. The hardness and elastic modulus of the coating decrease with increasing oxygen content due to phase transformation. The minimum friction coefficient of 0.52 and the lowest wear rate of 1.57 × 10−16 m3/(N∙m) at 600 °C are obtained for the coating deposited at 150 sccm, which is attributed to the excellent adhesion and thermal stability.