Wear and Corrosion Resistance of CrN Films on Oxynitriding-treated Vanadis 8 Tool Steel <i>via</i> the DC Magnetron Sputtering Process

Abstract

This research coated CrN films on oxynitriding-treated Vanadis 8 tool steel using the DC magnetron sputtering process of the PVD technique. The experimental parameters include different gas flow rates (Ar/N 2 was 20/20, 24/16, 28/12, and 32/8, respectively), with a bias of − 50 V, power of 100 W, deposition temperature of 300°C, and deposition time of 180 min, respectively. The experimental results show that Vanadis 8 tool steel can form an effective oxynitriding layer with a depth of about 50 μm after the oxynitriding treatment, and the surface hardness increased to about 1 400 HV0.05. Furthermore, the duplex coating layers exhibited optimal properties when the CrN films treated at an appropriate gas flow rate of Ar/N 2 was 24/16. Meanwhile, according to XRD analysis, the coating layer has a relatively high content of CrN composition, as well as the best wear resistance (the lowest specific wear rate when the loads of 2 N and 4 N were 2.05 × 10 − 5 and 1.56 × 10 − 5 mm 3 •m − 1 •N − 1 ) and good corrosion resistance (in a 3.5 wt% NaCl environment, I corr = 3.05 × 10 − 4 A•cm − 2 , R p = 362.52 Ω•cm 2 ). Overall, this study reveals that the CrN/oxynitriding duplex surface treatment could effectively improve the wear and corrosion properties of Vanadis 8 tool steel.

Improvement of the properties of CrN Films on oxynitriding treated Vanadis 23 high-speed steel by the DC magnetron sputtering

“…Furthermore, most literature points out that CrN lms have various preferential growths in the PVD process and that CrN lms have different growth directions under different coating parameters [9,14]. In this study, as the main diffraction peaks of different deposition temperatures were still the same degrees, this result is consistent with previous literature [4,9,14].…”

“…In this study, both the lowest corrosion current (8.9×10 − 5 A•cm − 2 ) and highest polarization resistance (822.11 Ω•cm 2 ) appeared in the 325℃ sample. Our previous studies indicated that the samples with a lower corrosion current (I corr ) and a higher polarization resistance (R P ) exhibited better corrosion resistance [4,6,7], thus, the 325℃-deposited CrN lms had the best corrosion resistance. It is speculated that the above phenomenon is mainly caused by the density difference on the surface of the CrN coating (as seen in Fig.…”

“…Therefore, this experiment also analyzed the water contact angles of CrN coatings prepared at different deposition temperatures. Previous literature found that a surface is hydrophilic when its contact angle (θ) is 90°, and hydrophobic when θ is 90° [4]. Generally speaking, materials with smaller water contact angles usually have better hydrophilicity, which can increase the wettability between the coating lm and the release agent on the material surface.…”

“…Surface treatments are necessary to further extend and improve the properties of Vanadis 23 applications, including wear and corrosion resistance. Our previous study indicated that the oxynitriding processes are the widely used surface modi cation techniques [4]. Generally speaking, the oxynitriding process can form several kinds of nitrides (Fe 2 N, Fe 3 N and Fe 4 N) and oxides (Fe 2 O 3 and Fe 3 O 4 ), which improve the wear, corrosion and erosion properties of the alloy steels [5,6].…”

“…Generally speaking, the oxynitriding process can form several kinds of nitrides (Fe 2 N, Fe 3 N and Fe 4 N) and oxides (Fe 2 O 3 and Fe 3 O 4 ), which improve the wear, corrosion and erosion properties of the alloy steels [5,6]. Notably, the oxynitriding layer can also effectively improve the adhesive strength as an intermediate layer during the duplex coating treatments [4][5][6][7].…”