Study On The Tribological And Corrosion Resistance Properties Of Carbide And Nitride Based Films In Water Environments

In this study, the TaN and Ta-DLC films were deposited by using DC magnetron sputteringsystem at different deposition parameters. The surface morphologies of the films and balls wereobserved by metallurgical microscope. The hardness was measured by using digital micro hardnesstester whilst the adhesion strength between the films and substrates was evaluated by the scratch tester;The phases of films was characterized using X-ray diffraction （XRD）; the surface roughness of filmsand worn surfaces on balls and films were analyzed by three-dimensional morphology microscope. Inaddition, the tribological properties of TaN coatings at different sliding velocity and Ta-DLC coatingsat different load were investigated in water by using ball-on-disk tribometer. Moreover, the anti-wearand anti-corrosion properties of Cr-DLC films in seawater with different salinity were alsocharacterized.The results showed that the optimized deposition parameters of TaN films were obtained as: theratio of gas flow is8:12（N2: Ar）, the applied power is100W, the negative bias is80V and the dutycycle is80%. The as-deposited TaN films exhibit low friction coefficient at high speed while theabrasion of TaN films and the grinding balls were serious. The Ta-DLC films deposited at acetylenegas flow of5sccm and15sccm performed excellent tribological properties, and the friction coefficientand the wear rate decreased gradually with increasing normal load. The lowest friction coefficient was0.081±0.007, while the wear rates of Ta-DLC films and Si₃N₄balls were1.0×10^-7mm³/Nm and2.1×10^-8mm³/Nm respectively. For the influence of salinity on the tribological and the anti-corrosionproperties of Cr-DLC films, it is clear that the lowest steady-state friction coefficient （0.081±0.008）was obtained in deionized water in comparison to that in seawater. Besides, the steady-state frictioncoefficient first decreased and then increased while the wear rates of films and balls increased with anincrease in the salinity. Specifically, the wear rate magnitude of balls was10-9mm³/Nm, lower thanthat of films by two orders of magnitude. The corrosion resistance of the Cr-DLC films in theseawater with salinity of30.04‰was best, while was the worst at the salinity of32.37‰.