Influence of nitrogen implantation on adhesion strength of TiAlN film on γ-TiAl alloy

Abstract Nitrogen implantation was utilized to improve the adhesion strength of TiAlN film on γ-TiAl alloy. The process involves nanometer-scale TiAlN film deposition by ion beam assisted deposition (IBAD), followed by successive nitrogen implantation and final TiAlN film deposition by IBAD. All processes were conducted in the same chamber without breaking vacuum. Adhesion strength of TiAlN films was evaluated using scratch test. Elemental depth profiles and bonding status in the mixed transition zone created by implantation were analyzed using X-ray photoelectron spectroscopy (XPS). Mechanical properties of the mixed transition zone were studied using nanoindentation. Nitrogen implantation significantly improves the adhesion strength of the TiAlN films. Mechanisms behind the improvement were explained in terms of the mixed transition zone formed and enhanced mechanical properties.