Improvement of the Wear and Corrosion Behaviors of DLC/oxynitriding Duplex-treated PM60 High-speed Steel <i>via</i> Various Power Densities of DC-pulsed Plasma Enhanced CVD

Abstract

In this study, diamond-like carbon (DLC) films are prepared by DC-pulsed plasma-enhanced chemical vapor deposition (PECVD) after the oxynitriding treatment of PM60 high-speed steel. The chief study of the parameters of a DC-pulsed PECVD process includes various power densities (200, 400, 600, 800 and 1 000 mW·cm − 2 ) with unipolar negative-pulsed voltage. In order to evaluate the properties of the DLC films for DLC/oxynitriding-treated PM60 high-speed steel, Raman spectroscopy analysis, wear tests, hardness tests, Rockwell indentation and corrosion resistance inspections are performed. The experimental results show the duplex coating layers to have the ideal properties when the DLC films are treated by the unipolar negative-pulsed voltage, a deposition time of 90 min and duty cycles maintained at 11%, with an appropriate power density (400 mW·cm − 2 ), respectively. The DLC/oxynitriding duplex treatment results in the highest surface hardness (Hv 0.2 2 516.4) and lowest wear volume loss (when the load of 2 N and 5 N is 2.36 × 10 − 3 mm 3 and 5.67 × 10 − 3 mm 3 , respectively). In addition, when the DLC/oxynitriding duplex film is treated by a power density of 200 mW·cm − 2 , it possesses the lowest corrosion current (I corr = 7.24 × 10 − 5 A·cm − 2 ) and highest polarization resistance (R p = 6.26 × 10 2 Ω·cm 2 ) in 3.5 wt% NaCl solutions. The test results confirm that the optimal wear and corrosion resistance can be acquired by the DLC/ oxynitriding duplex treatments.

Enhancement of the Wear and Corrosion Resistance of DLC/oxynitriding Duplex-treated PM30 Steel by the Asymmetric Bipolar-pulsed Plasma Enhanced CVD

“…In order to investigate the effects of the intermediate oxynitride layer, we consider our previous studies that have shown that the mechanical properties of DLC films are strongly affected by the hydrogen content, because hydrogen is a monovalent and acts to terminate potential carbon-carbon bonds. 1,7,8) An important potential benefit is that carbon clusters play a significant role in the growth of DLC films or crystalline diamonds. Furthermore, Gaussian function dismantling and synthesis are used to calculate the results of the integration area ratio (I D /I G ) and the offset of the G peak for the different gas flows of asymmetric bipolar pulsed plasma enhanced CVD.…”

“…Since the passivation layer generated a protective effect, our previous studies indicated that the samples with a lower corrosion current (I corr ) and a higher polarization resistance (R p ) evidenced better corrosion resistance. 1,7,8) A comparison of the corrosion resistance (I corr , E corr and R p ) for the different CH 4 gas flows of the DLC/oxynitride-treated PM30 specimens is shown in Table 1. The lowest corrosion current (1.43 × 10 − 4 A•cm − 2 ) and highest polarization resistance (5.32 × 10 2 Ω•cm 2 ) of the DLC/oxynitride-treated PM30 specimens appeared at a gas flow of 15 sccm, while the 3 sccm specimen possessed the highest corrosion current (3.89 × 10 − 4 A•cm − 2 ) and the lowest polarization resistance (2.48 × 10 2 Ω•cm 2 ).…”

“…Generally, a combination of high strength, wear resistance and hardness together with an appreciable toughness compared with other materials used as tools and fatigue resistance is required. 1) The PM30 family of high speed steels was developed in Sweden in the 1960's and is now widely used. 2) Among them, PM30 steel is a cobalt alloyed high performance PM high speed steel.…”

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

“…1,5) Our previous studies also indicated that oxygen addition can increase the efficiency of gas nitriding. [6][7][8][9] These better properties including higher surface hardness and better corrosion resistance, can be obtained by oxynitriding than those traditional nitriding, due to the oxides of Fe 3 O 4 and few Fe 2 O 3 . It is worth mentioning that the oxynitriding layer not only improves wear resistance but also enhances the adhesive strength as an intermediate layer.…”

“…It is worth mentioning that the oxynitriding layer not only improves wear resistance but also enhances the adhesive strength as an intermediate layer. 1,[6][7][8][9][10] Furthermore, chromium nitride (CrN) is known as potential protective material due to its high hardness, outstanding thermal stability and excellent wear properties. Moreover, CrN known as a corrosion resistant protective coating is one of the most attractive applications.…”