Structural and Tribological Analysis of Multilayer Carbon-Based Nanostructures Deposited via Modified Electron Cyclotron Resonance–Chemical Vapor Deposition

The electron cyclotron resonance–chemical vapor deposition (ECR-CVD) plasma coating method was employed to bombard steel surfaces to achieve high-strength carbon-based structures. The surfaces to be coated were rotated using an Arduino-controlled rotation system at different orientations to ensure a homogeneous coating. The samples were fixed 10 mm away from the plasma gun (CH4/N2 plasma). The samples were characterized via XRD, EDX, Raman spectroscopy, SEM, and AFM. The coated surfaces were then subjected to tribological tests, including the wear rate, coefficient of friction, and surface hardness–roughness. Thermally reduced graphene oxide with an average nanocrystalline size of 5.19–24.58 nm and embedded carbon nanotube structures with sizes ranging from 150 to 600 nm were identified, as well as less-defective microcrystallines and nanodiamonds. The results demonstrated that carbon coating in the presence of N2 gas led to a maximum reduction of 66% in the average wear rate, 14% improvement in the average surface hardness, 40% enhancement in the average coefficient of friction, and 48% enhancement in the average surface roughness. Consequently, a high-adhesion carbon-based coating deposited via plasma is likely to be a good candidate in the context of manufacturing engineering steels with a low friction coefficient, low wear rate, and long service life.