Improvement of the Wear Resistance and Corrosion Properties of CrN Films on Oxynitriding-Treated Vanadis 23 High-Speed Steel by the DC Magnetron Sputtering Process

Abstract

This study coated CrN films onto oxynitriding-treated Vanadis 23 high-speed steel using the DC magnetron sputtering process of the PVD technique. The experimental parameters include various deposition temperatures (275, 300, 325, and 350°C), a bias of -25 V, a power of 100 W, a gas flow rate of 45/30 (Ar/N2) sccm, and a deposition time of 2.5 h. The research results show that Vanadis 23 high-speed steel formed an effective oxynitriding layer with a depth of about 50 μm after the oxynitriding treatment, and the surface hardness increased to 1100 HV0.05. Furthermore, when the coatings were deposited at 325°C, the CrN coatings possessed an obvious columnar crystal structure, the highest hardness (13.4 GPa), and the highest elastic modulus (159.7 GPa). In addition, the CrN coating had the best wear properties (the lowest specific wear rates were 1.07×10-6 and 1.33×10-6 mm3·m-1·N-1 under the loads of 2 N and 4 N, respectively) and good corrosion resistance (corrosion current was 8.90×10-5 A·cm-2, and polarization resistance was 822.11 Ω·cm2 in a 3.5 wt% NaCl solution).