Synergistic effects of heat and hydration treatments on mechanical and electrochemical characteristics of AlTiN coatings

This research investigated the synergistic effects of heat and hydration treatments on the mechanical and electrochemical characteristics of AlTiN-coated specimens. X-ray diffraction analysis presented no phase transitions due to such treatments. However, the intensity of the (Al,Ti)N crystalline phase weakened upon the interaction between the oxidation and hydration treatments. The additional TiN and TiO2 crystalline phases were observed. Most of the oxides that formed in the microparticles on the surfaces of the specimens were Ti oxides, which had both polygonal and needle-shaped structures. Polygonal Ti oxides, which are relatively stable in nature, were found in higher proportions in the specimens with hydration after heat treatment. Such specimens also exhibited superior mechanical and electrochemical characteristics. This phenomenon is attributed to the positive effect of the interaction between the rearrangement of lattice structures via heat treatment and the formation of oxide films through hydration treatment. In contrast, the specimens heat-treated after hydration suffered from the negative effect of the treatments on each other, resulting in a slight degradation in mechanical and electrochemical characteristics. Therefore, the appropriate sequencing of heat and hydration treatments is crucial to maximizing their effects.