Influence of nitrogen addition on the wear performance of lightweight (AlCoCrNiSiTi)100-xNx thin films developed by magnetron sputtering

(AlCoCrNiSiTi) 100-x N x thin films were developed using a pulsed DC four-source closed field magnetron sputtering system with varying nitrogen gas flow ratios (R N = 0, 0.25, and 0.40). The impact of nitrogen addition on the elemental composition, deposition rate, morphology, roughness, and microstructure are examined in this work. With a rise in the nitrogen content, all thin films showed an amorphous structure and a greater presence of covalent nitride bonds with light-weight elements such as Al, Si, and Ti. Hardness increased significantly with the addition of nitrogen, rising from 7.9 ± 0.6 GPa to 10.2 ± 0.3 GPa. The thin film with the highest nitrogen content demonstrated superior wear resistance, as indicated by the highest H/E r and H 3 /E r 2 ratios. Microtribological testing under dry air conditions revealed a notable enhancement in wear resistance with the addition of nitrogen, reducing the wear rate from 1.76-2.63 × 10 -6 mm 3 /Nm for the nitrogen-free thin film to 0.18–0.37 × 10 -6 mm 3 /Nm for the thin film deposited at R N = 0.40. Further analysis using Schiffmann’s model highlighted a shift from plastic-dominated behavior in nitrogen-free thin films to elastic-dominated behavior in nitrogen-containing thin films, presenting the correlation between mechanical properties and wear resistance of the developed thin films.