Structural and tribological properties of CrMoCN coatings with various Mo contents in artificial seawater

CrMoCN coatings with various Mo contents were prepared on Ti6A14V disks and Si wafers using unbalanced magnetron sputtering at various Mo target currents, and their crystallite phases and bonding structures were characterized using XRD and TEM as well as XPS, respectively. The mechanical properties of coatings were measured by nano-indenter and the tribological properties of CrMoCN/SiC tribopairs in artificial seawater were tested by ball-to-disk tribo-tester. The results showed that Cr, Mo and N elements mainly existed in the form of (Cr, Mo)N solid solution crystals, while C element mainly existed as amorphous a-C and amorphous a-CNx. The hardness and elastic modulus of CrMoCN coatings increased first, and then decreased as Mo target current further increased to 3.0 A. The friction coefficients and wear rates of CrMoCN/SiC tribopairs decreased overall with the increase in the Mo target current due to the synergistic lubrication and wear-reducing effect of tribolayers (MoO3 and SiO2 center dot 2H(2)O). The abrasive and tribo-chemical wear were the wear mechanisms of CrMoCN/ SiC tribopairs. CrMoCN-3.0 coating showed the best tribological properties in the artificial seawater.