The Effect of Bias Voltage and Acetylene Gas Flow Rate on the Wear Behavior of Diamond-like Carbon Coatings on M2 High-Speed Steel

Abstract

This paper investigates the impact of bias voltage and acetylene flow rate on the mechanical, structural, and scratch performance of diamond-like carbon (DLC) coated high-speed steel (HSS) M2 commonly used in hydraulic vane pumps. The DLC coatings were produced through plasma-enhanced chemical vapour deposition, with micro-Raman spectroscopy used to analyze their structure via G-peak and D-peak measurements. Results showed that DLC deposited at 350 V and 100 sccm demonstrated high hardness (28.99 GPa) and modulus of elasticity (308.1 GPa), with the highest critical load of 167.246 mN indicating superior adhesion to the HSS M2 substrate at a higher bias voltage and lower flow rate. The minimum wear rate of 3.02 × 10−3 mm3/Nm was achieved with a thinner DLC coating deposited at 350V bias voltage and 100 sccm acetylene flow rate.