Scratch response and tribological properties of TiAlSiN coatings deposited by reactive deep oscillation magnetron sputtering

TiAlSiN nanocomposite coatings were deposited using deep oscillation magnetron sputtering with various nitrogen flow ratio (f_N2) of 0%-20%. The increase of f_N2 promotes phase separation from a single crystallographic TiAlSi to nc-(Ti,Al)N/a-Si₃N₄ phase. The introduce of N content leads to the formation of refined grain size, smooth morphologies and dense microstructure. Ti_0.15Al_0.39Si_0.07N_0.39 coatings with (Al + Si)/Ti ratio of 2.9 deposited at f_N2 = 10% reach the highest hardness of 32.8 GPa, H/E∗ of and 0.0837 and H³/E∗² of 0.23. The introduce of N leads to failure mode changing from brittle tensile cracking (through-thickness cracking) to buckle spallation (interfacial failure). Ti_0.15Al_0.39Si_0.07N_0.39 coatings with highest H, H/E∗ and H³/E∗² ratios show buckling failure with high L_C1 of 25.4 N and L_C3 of 43.6 N. Correspondingly, Ti_0.15Al_0.39Si_0.07N_0.39 coatings are subjected to oxidation wear with low coefficient of friction of 0.41 and specific wear rate of 0.39