Atomic-scale stress release and structure–tribology correlations in alternating-energy DLC films under harsh load conditions

Abstract

Diamond-like carbon (DLC) films have attracted significant attention in the field of microscale mechanical components owing to their exceptional tribological properties and chemical inertness. However, the intricate interaction between residual stress and structural integrity poses substantial challenges for their widespread application, particularly under harsh load conditions. This study investigates the deposition and friction behaviors of alternating-energy DLC films under a high contact pressure of 20 GPa using molecular dynamics simulations. By comparing the single- and alternating-energy deposition schemes, this study focuses on the modulation ratio, residual stress distribution, and friction-wear characteristics. The results reveal that alternating-energy deposition significantly reduces residual stress, with values dropping to -3.7 and 0.1 GPa for the 1-70 and 70-1 eV systems, respectively, representing an up to 99 % reduction compared to single-energy deposition. Friction behavior analysis demonstrates that high-energy-terminated deposition systems (70 and 1-70 eV) exhibit low friction coefficients, which was attributed to the formation of a stable, saturated amorphous carbon network at the sliding interface. Quantitative wear rate analysis revealed that the alternating interfacial structure in the alternating-energy deposition system can compromise its wear resistance performance. This study enhances the understanding of DLC multilayer systems under extreme conditions and provides theoretical guidance for the design of stress-relieved and wear-resistant carbon coatings with tailored nanoscale structures.