Deposition, microstructure and mechanical and tribological properties of magnetron sputtered TiN/TiAlN multilayers

By using unbalanced magnetron sputtering, TiN/TiAlN multilayers with bilayer lengths from 10 nm to 30 nm and thickness of 3 μm were deposited on steel substrates. The multilayer microstructure was characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy; and the chemical composition by Rutherford backscattering and elastic recoil detection analysis. The mechanical properties were investigated by nanoindentation and stress measurements, where the radius of curvature of the substrate was measured. Tribological properties were obtained by pin-on-disc measurements. Similar hardness values were observed for the multilayers and the single-layer coatings, while large improvements of the wear properties were observed for the multilayers compared to the single-layer coatings. This was connected to a change in wear mechanism, the adhesive wear being significantly reduced in the multilayers.