Amorphous carbon and carbon nitride multilayered films prepared by shielded arc ion plating

Multilayered films consisting of amorphous carbon (a-C) and carbon nitride (a-CN) have been prepared by shielded arc ion plating (SAIP). Hardness and wear resistance of the multilayered films were measured with a nanoindenter interfaced with an atomic force microscope (AFM). Friction coefficients of the multilayered films were determined as well against a SUJ2 (SAE 52100) bearing ball using a ball-on-disc tribo-tester. The a-CN films deposited on a hard a-C film prepared at Vb=0 or −300 V were harder than the single a-CN films directly deposited on the silicon substrate. The hardness of these layered samples was 4 GPa greater than that of the single layers. The hardness of a-C (60 nm)/a-CN (60 nm, Vb=−300 V)/a-C (120 nm) triple layer film was 5 GPa higher than that of the single layered a-C. The wear resistance of the all layers was better than sapphire, although sapphire is harder than the single and double layers. The friction coefficients of the triple layers were low and stable. The triple layer showed the lowest friction coefficient of about 0.1.