The effect of carbon doping on microstructure, mechanical properties, wear resistance and cutting performance of AlTiCN coating

A series of AlTiCN coatings with different carbon contents (0-0.7 at.%) were deposited on YG10 (WC + 10 wt.% Co) cemented carbide by cathodic arc-evaporation of Ti-Al/Ti-Al-C targets in a mixture of Ar and N-2 gases. The influence of carbon doping on microstructure, mechanical properties, wear resistance and cutting performance was systematically investigated by comparing carbon-free coating and coatings with different carbon contents. The microstructure of the coatings has been changed significantly with the addition of C, and the amorphous domains appear when the doping amount of C is among 0.2-0.5 at.%. Instead of forming bonds with other elements in the coating, carbon only acts as a growth inhibitor. When the carbon content is 0.2 at.%, the hardness of the coating significantly decreased, but changes a little with the carbon content continue to rise. The addition of C significantly improves the wear resistance of the coating, which is mainly attributed to the transformation of the crystalline state and the formation of the dense Al2O3 oxide layer. Among them, the coating with a carbon content of 0.2 at.% has both excellent wear resistance and cutting performance.