Influence of substrate rotation speed on the structure and mechanical properties of nanocrystalline AlTiN/MoN coatings synthesized by cathodic arc ion-plating

We have investigated the effects of substrate rotation speed (SRS) on the structural and mechanical properties of AlTiN/MoN multilayer coatings produced by cathodic arc ion-plating using 2-fold rotation technique on Si (100) and cemented carbide substrates. The Al:Ti ratios measured by EDS over all samples are closed to design 2:1 ratio and corresponds to Al0.63Ti0.37 N composition. The bilayer periods are in the range of 11-61 nm depending on rotation speed. The 3 round per minute (RPM) coating exhibits the smoothest surface (Rms = 19 nm) and 1 RPM highest hardness of 44 GPa. Hardness and Young's modulus decrease with increasing RPM. Hardness, Young's modulus, smoothness and friction coefficient of multilayer structures are higher in comparison with single layer counterparts. Wear track and surface morphology experiments have also been analyzed.