Kumar, R., Bharti, P., Dhand, C., Yeo, R. J., Zhang, M., & Dwivedi, N. (2023). “It’s team work”: Multilayered wear-resistant and lubricating overcoats derived from the synergy of ultrathin carbon surface and interface chemistry. Applied Surface Science, 641, 158485. https://doi.org/10.1016/j.apsusc.2023.158485
Abstract:
High friction and wear remain the major concerns in moving mechanical assemblies (MMAs), leading to an excessive amount of wasted energy and premature system failure. While the use of protective overcoats on the moving surfaces is a common solution to overcome these limitations, achieving excellent tribological characteristics at ultrathin overcoat thicknesses remains very challenging. Here, by combining the benefits arising from an enhanced carbon surface and a robust substrate-overcoat interface chemistry, we report the development of tribologically resilient sub-5 nm carbon-based overcoats on mechanically soft metallic alloy substrates which show considerably lower friction and higher wear resistance than commercially grown overcoats. The use of an interlayer coupled with an energetic process for carbon growth not only enhanced the sp3 carbon bonding content but also promoted interatomic mixing and the formation of hybrid bonds that significantly improved the interfacial strength and hence the substrate-overcoat adhesion, demonstrating excellent wear resistance in a rigorous tribological environment. Moreover, further modifying the overcoat surface with a composite layer of multilayer graphene flakes and multiwall carbon nanotubes was shown to immensely boost the lubricity and wear durability.
License type:
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
Funding Info:
This research was supported by the Science and Engineering Research Board (SERB), India, under the project code SRG/2021/000105.