Correlation of Microstructural and Mechanical Properties of CVD Deposited TiAlN Coatings

Titanium aluminum nitride (TiAlN) thin films were synthesized with different N2 flow rate on p-type Si (100) substrate and characterized by FESEM, AFM, XRD and nanoindentation to investigate the morphology, structural and mechanical properties. The FESEM images revealed non-uniform grain distribution with a higher degree of pores with the increase in N2 flow rate. The XRD data indicated the presence of AlN, TiAlN, Al2O3 dominant phases at 33.07°, 55.5°, 61.79° and 47.84°, 54.67° diffraction angles attributed to (100), (220) and (400), (112) diffraction plane, respectively. The AFM images revealed the average roughness as 36.9 nm for 30 sccm N2 flow rate. Furthermore, the mechanical properties such as H, E, plasticity index (H/E) and deformation to plastic resistance (H3/E2) of TiAlN thin film were found to be 21 GPa, 400 GPa, 0.094 and 0.318 GPa, respectively, indicating higher resistance to crack with increasing N2 flow rate.