Deposition of DLC Films onto Oxynitriding-Treated V4E High Vanadium Tool Steel through DC-Pulsed PECVD Process

Abstract

In this work, DLC lms are prepared by DC-pulsed PECVD after the oxynitriding treatment of V4E high vanadium tool steel. The experimental design includes various power densities (200, 400, 600 and 800 mW·cm ) with an unbalanced bipolar-pulsed voltage. The deposition time is 90 min, and the CH 4 gas ow is maintained at 5 sccm, respectively. The experimental results show the duplex coating layers to have better properties when the DLC lms are treated by an appropriate power density (400 mW·cm ) and the highest polarization resistance (258.83 Ω·cm 2 ) after the 3.5 mass% NaCl corrosion test. This study con rms that the wear and corrosion resistance of V4E tool steel can be effectively improved through the DLC/oxynitriding duplex treatment.

Optimization of DLC films on oxynitriding-treated Vanadis 10 tool steel through the various duty cycles of DC-pulsed plasma-enhanced CVD

“…A comparison of the corrosion resistance for the different duty cycles of DLC/oxynitriding treated V10 specimens is shown in Table 1. Our previous studies have shown that the samples with a lower current density (I corr ) and high polarization resistance (R P ) evidenced better corrosion resistance [4,5]. In this study, the lowest corrosion current (7.9 × 10 −5 A cm −2 ) and highest polarization resistance (1185.21 Ω cm 2 ) of the V10 specimens appeared at the 17 % duty cycle.…”

“…As mentioned previously, the oxynitride layer improved not only wear and corrosion resistance but also the intermediate layer. Previous studies indicated that an oxynitride layer could increase DLC films' adhesive strength since passive oxide film (Fe 3 O 4 ) can be used to decrease the microporous structure during the nitriding process [4,5]. In the study, hard and brittle δ-Fe 2 N phases were not found; therefore, the surface brittleness of the oxynitriding layer could be significantly improved.…”

“…It has been found that using intermediate layers between the DLC film and the substrate can increase the adhesion strength of the film [13,14]. As studied previously, the oxynitriding layer improves the corrosion properties and the adhesive strength as an interlayer [3][4][5]. Therefore, this research utilized DC-pulsed plasmaenhanced CVD and DLC/oxynitriding duplex treatments to study the characteristics of DLC films and improve the coating properties of V10 tool steel.…”

“…Particularly, the Fe 3 O 4 layer of oxidation treatment can effectively protect and improve steels' erosion and corrosion resistance. Our previous studies showed that the oxynitriding layer could form the passive oxidative film, which improved the adhesive strength as an intermedi-ate layer during the duplex coating treatments [3][4][5].…”

“…Several different techniques have been used for depositing DLC films, such as PVD, RF magnetron sputtering, plasma enhanced chemical vapor deposition (CVD), and ion beam deposition in recent years. Among them, the most common deposition technique of DLC films is plasma-enhanced CVD [5]. It is worth mentioning that the DC-pulsed plasmaenhanced CVD is a novel method because it is simpler and can be used on an industrial scale at a lower cost [9][10][11][12].…”