Surface morphology and tribological properties of DC sputtered nanoscale multilayered TiAlN/CNx coatings

In this study, TiAlN/CNx multilayer and TiAlN monolayer coatings with a CNx top layer were deposited using a reactive DC magnetron sputtering system on cemented carbide tool steel and Si(100) substrates. The morphology and microstructure of the coatings were observed by atomic force microscopy in the dynamic friction mode and transmission electron microscopy. Tribological properties of the coatings were evaluated by pin-on-disc friction testing in dry air, and high-frequency linear-oscillation friction testing in dry air, and under water boundary lubrication conditions. The coatings with a CNx top layer showed better wear behavior and friction coefficients as low as 0.23 and 0.22 for water boundary lubrication. The excellent tribological properties of these composition coatings correspond to their surface morphology and roughness.