The Effect of the Ar:N2:O2 Flow Ratio on the Structure, Hardness, and Adhesion of Thin TiON Films

This study investigates the effect of the gas mixture composition ratio (Ar:N2:O2) during magnetron sputtering on the morphology, phase composition, and visual characteristics of TiNxOy thin films. Five different modes were used with a variable N2:O2 ratio ranging from 0.5 to 3. The resulting coatings exhibited noticeable differences in color—from golden to dark blue—which correlates with changes in chemical composition and phase state. The morphology of the films, examined by scanning electron microscopy (SEM), varied from a dense to a columnar structure. These results demonstrate that the properties of TiON coatings can be controlled by adjusting the N2:O2 ratio: nitrogen-rich conditions promote denser coatings with higher hardness and improved wear resistance, whereas a balanced N2:O2 ratio enhances coating adhesion to the substrate.