Characterization of pulsed plasma nitriding and physical vapor deposition duplex-treated CrAlN coatings

To enhance the adhesion, hardness, and wear resistance of CrAlN coatings deposited via physical vapor deposition, this paper proposes a method involving stepwise and in-situ nitriding and coating composite treatment using pulsed plasma nitriding and multi-arc ion plating technology to prepare a nitrided-coated CrAlN layer on AISI D2 steel. The microstructural and mechanical properties of the coatings are investigated. The results indicate that the CrAlN coating exhibits a (111) texture orientation, with the diffraction intensity weakened in the stepwise processed coating, while the in-situ processed coating shows a (200) texture orientation. The adhesion strength of the in-situ processed coating reaches 66.32 N, achieving an adhesion level of HF1, with a surface hardness of 3279 HV0.025 and a wear rate of 1.85 × 10^-15 m³/N·mm. The in-situ processed coating demonstrates superior resistance to crack propagation and exhibits excellent wear resistance.