Regulatory mechanism of N₂ flow rate on structure and properties of CrAlNiYN coatings by FCVA technique

In this work, a novel CrAlNiYN coating was prepared by filter cathode vacuum arc (FCVA) technique. The evolution of the microstructure and properties of the coatings with varying N₂ flow rates was systematically investigated. The results revealed that as the N₂ flow rate increased from 10 to 90 sccm, the N content in the coating increased from 2.54 to 46.20 at.%, while the Ni content significantly decreased from 67.54 to 31.15 at.%. Simultaneously, the phase structure transitioned from the intermetallic compound AlNi₃ to the solid solution Al(Cr)N. This transformation, along with solid solution strengthening and grain refinement, resulted an increase in hardness from 13.4 ± 0.4 to 26.6 ± 0.6 GPa. Moreover, the H/E, H³/E² and W_e values also displayed a gradually increasing trend, indicating improved resistance to plastic deformation. However, the adhesion strength presented a weakening trend from HF1 to HF3. Furthermore, the corrosion current density of coatings first increased and then slightly decreased with the increase of N₂ flow rate, while the polarization resistance had the opposite trend of change. Among them, the coating at 10 sccm exhibited the best corrosion resistance, with the lowest i_corr of 0.150 μA cm⁻² and the highest R_p of 302.1 kΩ cm².